Systems and methods for minimizing energy available to contacts during a fault

ABSTRACT

A system may include a relay device that includes armatures associated with phases of voltage signals. The system may also include relay coils, such that each relay coil may receive a respective voltage that magnetizes a respective relay coil, thereby causing the respective armature to move from a respective first position to a respective second position. The system may also include a control system that receive an indication that a fault condition is present, identify a first phase of the phases of voltage signals that is expected to be the next phase of the phases to cross zero, and send a signal to the relay device in response to identifying the first phase. The signal is configured to cause a first relay coil of the relay coils to energize or deenergize.

BACKGROUND

The present disclosure relates generally to switching devices, and moreparticularly to operation and configuration of the switching devices.

Switching devices are generally used throughout industrial, commercial,material handling, process and manufacturing settings, to mention only afew. As used herein, “switching device” is generally intended todescribe any electromechanical switching device, such as mechanicalswitching devices (e.g., a contactor, a relay, air break devices, andcontrolled atmosphere devices) or solid-state devices (e.g., asilicon-controlled rectifier (SCR)). More specifically, switchingdevices generally open to disconnect electric power from a load andclose to connect electric power to the load. For example, switchingdevices may connect and disconnect three-phase electric power to anelectric motor. As the switching devices open or close, electric powermay be discharged as an electric arc and/or cause current oscillationsto be supplied to the load, which may result in torque oscillations. Tofacilitate reducing likelihood and/or magnitude of such effects, theswitching devices may be opened and/or closed at specific points on theelectric power waveform. Such carefully timed switching is sometimesreferred to as “point on wave” or “POW” switching. However, the openingand closing of the switching devices are generally non-instantaneous.For example, there may be a slight delay between when the makeinstruction is given and when the switching device actually makes (i.e.,closes). Similarly, there may be a slight delay between when breakinstruction is given and when the switching device actually breaks(i.e., opens). Accordingly, to facilitate making or breaking at aspecific point on the electric power waveform, a number of embodimentsmay be employed to enable the switching device to operate with respectto a specific point on the electrical power waveform. As such, thepresent disclosure relates to various different technical improvementsin the field of POW switching, which may be used in various combinationsto provide advances in the art.

BRIEF DESCRIPTION

A summary of certain embodiments disclosed herein is set forth below. Itshould be understood that these aspects are presented merely to providethe reader with a brief summary of these certain embodiments and thatthese aspects are not intended to limit the scope of this disclosure.Indeed, this disclosure may encompass a variety of aspects that may notbe set forth below.

In one embodiment, a system may include a relay device that includesarmatures associated with phases of voltage signals. The system may alsoinclude relay coils, such that each relay coil may receive a respectivevoltage that magnetizes a respective relay coil, thereby causing therespective armature to move from a respective first position to arespective second position. The system may also include a control systemthat receive an indication that a fault condition is present, identify afirst phase of the phases of voltage signals that is expected to be thenext phase of the phases to cross zero, and send a signal to the relaydevice in response to identifying the first phase. The signal isconfigured to cause a first relay coil of the relay coils to energize ordeenergize.

DRAWINGS

These and other features, aspects, and advantages of the presentdisclosure will become better understood when the following detaileddescription is read with reference to the accompanying drawings in whichlike characters represent like parts throughout the drawings, wherein:

FIG. 1 is a diagrammatical representation of a set of switching devicesto provide power to an electrical load, in accordance with anembodiment;

FIG. 2 is a similar diagrammatical representation of a set of switchingdevices to provide power to an electrical motor, in accordance with anembodiment;

FIG. 3 is a similar diagrammatical representation of a set of switchingdevices to provide power to an electrical motor, in accordance with anembodiment;

FIG. 4 is a perspective view of a single-pole, single current-carryingpath switching device, in accordance with an embodiment;

FIG. 5 is a perspective exploded view of the device of FIG. 4, inaccordance with an embodiment;

FIG. 6 is a system view of an example single-pole, singlecurrent-carrying path relay device, in accordance with an embodiment;

FIG. 7 is a current-time graph for a relay device operating using anominal voltage, in accordance with an embodiment;

FIG. 8 is a current-time graph for various relay devices having variouscoil inductance operating with a voltage that corresponds to a rating ofa respective coil in a respective relay device, in accordance with anembodiment;

FIG. 9 is a current-time graph for various relay devices having variouscoil inductance operating with a voltage that is higher than a rating ofa respective coil in a respective relay device, in accordance with anembodiment;

FIG. 10 is a circuit diagram for providing a constant current to a coilof a relay device, in accordance with an embodiment;

FIG. 11 is a current-time graph that depicts the coil current in twocoils of two relays that are driven by a constant current source and aconstant voltage source, respectively, in accordance with an embodiment;

FIG. 12 is a position-time graph that depicts armature positions overtime with respect to various coil resistances for various relay devices,in accordance with an embodiment;

FIG. 13 is an inductance-current graph that depicts the coil currents invarious relay devices having various armature positions that are drivenby a constant current source and a constant voltage source, inaccordance with an embodiment;

FIG. 14 is a current-time graph that depicts a relationship between thecurrent of a number of coils in a number of relay devices having variouscoil resistances with respect to time when the respective coil is drivenby a constant current source and a constant voltage source, inaccordance with an embodiment;

FIG. 15 illustrates a voltage-time graph that depicts a relationshipbetween the voltage change in a relay coil when the relay coil is drivenwith a constant voltage source versus a constant current source, inaccordance with an embodiment;

FIG. 16 illustrates an example position-time graph that depicts aposition of the armature over time, in accordance with an embodiment;

FIG. 17 illustrates an example circuit that may be employed to addexternal inductance to a relay coil, in accordance with the embodimentsdescribed herein;

FIG. 18 illustrates a current-time graph that depicts a pulsed coilcurrent being provided to a relay coil, in accordance with anembodiment;

FIG. 19 illustrates a pulsed coil current graph that includes a coilcurrent curve relative to an armature position curve, in accordance withan embodiment;

FIG. 20 illustrates a process implemented on specialized circuitry thatmay be employed to control POW close and open operations byde-energizing operations, in accordance with an embodiment;

FIG. 21 illustrates an example circuit for arcing mitigation, inaccordance with an embodiment;

FIGS. 22 and 23 illustrate example circuitry for load balancing ofoperations on contacts and connection redundancy, in accordance with anembodiment;

FIG. 24 illustrates an example three-pole relay circuit which uses POWtechniques to provide reliable operation with a reduced number ofcontacts, in accordance with an embodiment;

FIGS. 25 and 26 illustrate processes and associated circuitry states forcontact erosion mitigation in an electromechanical switching device(e.g. like the one in FIG. 24), in accordance with an embodiment;

FIG. 27 illustrates a flow chart of a method for opening contacts of arelay device during a fault condition, in accordance with an embodiment;

FIG. 28 illustrates a flow chart of a method for controlling powerprovided to a relay device during a disruptive event, in accordance withan embodiment;

FIG. 29 illustrates a flow chart of a method for controlling an actuatorto open contacts based on a change in current value, in accordance withan embodiment;

FIG. 30 is a system view of an example single-pole, singlecurrent-carrying path relay device with an actuator, in accordance withan embodiment;

FIG. 31 illustrates a flow chart of a method for controlling an actuatorto positions contacts for an open operation based on a position of anarmature of in a relay device, in accordance with an embodiment;

FIG. 32 illustrates a flow chart of a method for controlling an actuatorto position contacts for a close operation based on a position of anarmature of in a relay device, in accordance with an embodiment;

FIG. 33 illustrates a flow chart of a method for dynamically configuringPOW settings for a relay device, in accordance with an embodiment;

FIG. 34 illustrates a flow chart of a method for dynamically adjustingPOW settings for a relay device based on protection equipment data, inaccordance with an embodiment;

FIG. 35 illustrates a flow chart of a method for coordinating activationof multiple devices with respect to POW settings for multiple respectiverelay devices, in accordance with an embodiment;

FIG. 36 illustrates a flow chart of a method for dynamically controllinga beta delay for a relay device based on harmonics data, in accordancewith an embodiment;

FIG. 37 illustrates a flow chart of a method for dynamically controllinga beta delay for a relay device based on a presence of a magnetic core,in accordance with an embodiment;

FIG. 38 illustrates a flow chart of a method for implementing a softstart initialization process using POW switching, in accordance with anembodiment;

FIG. 39 illustrates a flow chart of a method for reconnecting power to arotating load, in accordance with an embodiment;

FIG. 40 illustrates a flow chart of a method for reconnecting power to arotating load based on back electromotive force (EMF), in accordancewith an embodiment;

FIG. 41 is a perspective view of an exemplary printed circuit board(PCB) implementing a single motor controller, in accordance with anembodiment;

FIG. 42 is a schematic representation of the motor controller of FIG.41, in accordance with an embodiment;

FIG. 43 is a diagrammatical view of exemplary control circuitry of themotor controller of FIG. 41, in accordance with an embodiment;

FIG. 44 is a simplified representation of an exemplary PCB implementingmultiple motor controllers, in accordance with an embodiment; and

FIG. 45 is a flowchart of a method for an initialization process toautomatically adjust circuit connections on the PCB of FIG. 44 to routewires between motors coupled to the PCB and motor controllers coupled tothe PCB, in accordance with an embodiment.

DETAILED DESCRIPTION

One or more specific embodiments of the present disclosure will bedescribed below. In an effort to provide a concise description of theseembodiments, all features of an actual implementation may not bedescribed in the specification. It should be appreciated that in thedevelopment of any such actual implementation, as in any engineering ordesign project, numerous implementation-specific decisions must be madeto achieve the developers' specific goals, such as compliance withsystem-related and business-related constraints, which may vary from oneimplementation to another. Moreover, it should be appreciated that sucha development effort might be complex and time consuming, but wouldnevertheless be a routine undertaking of design, fabrication, andmanufacture for those of ordinary skill having the benefit of thisdisclosure.

When introducing elements of various embodiments of the presentdisclosure, the articles “a,” “an,” “the,” and “said” are intended tomean that there are one or more of the elements. The terms “comprising,”“including,” and “having” are intended to be inclusive and mean thatthere may be additional elements other than the listed elements.

As described above, switching devices are used in variousimplementations, such as industrial, commercial, material handling,manufacturing, power conversion, and/or power distribution, to connectand/or disconnect electric power from a load. To consistently implementPOW switching, a number of factors may be taken into consideration toensure that the respective switching device closes or opens within aconsistent amount of time after receiving a signal causing therespective switching device to close or open. That is, a coil drivecircuit that controls the closing and opening of the switching devicemay be affected by a coil resistance, a temperature, a coil supplyvoltage, a coil inductance, and the like. The present embodimentsdescribed herein assists the switching device to close or open within aconsistent time frame that may enable the POW switching operations to bemore effective.

With the foregoing in mind, it should be noted that an ideal inductorcurrent is expected to be linear when coupled to a constant voltagesource. That is, the inductor current (i) is inversely proportional tothe coil inductance (L) when coupled to a constant voltage source(v(t)), as described below in Equation 1.

$\begin{matrix}{{v(t)} = {\left. {L\frac{di}{dt}}\rightarrow i \right. = {\left. {\frac{1}{L}{\int_{0}^{t}{v\mspace{14mu} {dt}}}}\rightarrow{i(t)} \right. = {\frac{1}{L}({vt})}}}} & (1)\end{matrix}$

However, due to the change in inductance of the coil as the armature ofthe switching device (e.g., relay device) moves, the coil current is notlinear when a voltage that corresponds to the rating of the coil isapplied to the coil. With this in mind, in some embodiments, a voltagesource that outputs a voltage that is higher (e.g., 4 to 5 times higher)than the rated voltage of the coil. The higher voltage may significantlyreduce the variability of the time in which various switching devicescloses due to the coil current reaching a threshold current value withina shorter amount of time as compared to when the rated voltage isapplied to the coil for the same various switching devices. In otherwords, driving the coil using a higher voltage source than the voltagerating for the respective coil will minimize the effect of inductancevariability in the coil on the operation (e.g., close time) of theswitching device.

In addition to using a higher voltage source as compared to the ratingof the coil, the present embodiments may also employ a constant currentsource to drive the coil. The constant current source may enable theswitching device to close more consistently over various coilresistances (e.g., +/−10%), various temperatures (e.g., additional+/−10% on coil resistance), various coil supply voltages (e.g., +/−5%).Additional details for employing a constant current source with arelatively high voltage source to drive the coil of a switching deviceis described below with reference to FIGS. 1-14.

By way of introduction, FIG. 1 depicts a system 10 that includes a powersource 12, a load 14, and switchgear 16, which includes one or moreswitching devices that may be controlled using the techniques describedherein. In the depicted embodiment, the switchgear 16 may selectivelyconnect and/or disconnect three-phase electric power output by the powersource 12 to the load 14, which may be an electric motor or any otherpowered device. In this manner, electrical power flows from the powersource 12 to the load 14. For example, switching devices in theswitchgear 16 may close to connect electric power to the load 14. On theother hand, the switching devices in the switchgear 16 may open todisconnect electric power from the load 14. In some embodiments, thepower source 12 may be an electrical grid.

It should be noted that the three-phase implementation described hereinis not intended to be limiting. More specifically, certain aspects ofthe disclosed techniques may be employed on single-phase circuitryand/or for applications other than power an electric motor.Additionally, it should be noted that in some embodiments, energy mayflow from the source 12 to the load 14. In other embodiments energy mayflow from the load 14 to the source 12 (e.g., a wind turbine or anothergenerator). More specifically, in some embodiments, energy flow from theload 14 to the source 12 may transiently occur, for example, whenoverhauling a motor.

In some embodiments, operation of the switchgear 16 (e.g., opening orclosing of switching devices) may be controlled by control andmonitoring circuitry 18. More specifically, the control and monitoringcircuitry 18 may instruct the switchgear 16 to connect or disconnectelectric power. Accordingly, the control and monitoring circuitry 18 mayinclude one or more processors 19 and memory 20. More specifically, aswill be described in more detail below, the memory 20 may be a tangible,non-transitory, computer-readable medium that stores instructions, whichwhen executed by the one or more processors 19 perform various processesdescribed. It should be noted that non-transitory merely indicates thatthe media is tangible and not a signal. Many different algorithms andcontrol strategies may be stored in the memory and implemented by theprocessor 19, and these will typically depend upon the nature of theload, the anticipated mechanical and electrical behavior of the load,the particular implementation, behavior of the switching devices, and soforth.

Additionally, as depicted, the control and monitoring circuitry 18 maybe remote from the switchgear 16. In other words, the control andmonitoring circuitry 18 may be communicatively coupled to the switchgear16 via a network 21. In some embodiments, the network 21 may utilizevarious communication protocols such as DeviceNet, Profibus, Modbus, andEthernet, to mention only a few. For example, to transmit signalsbetween the control and monitoring circuitry 18 may utilize the network21 to send make and/or break instructions to the switchgear 16. Thenetwork 21 may also communicatively couple the control and monitoringcircuitry 18 to other parts of the system 10, such as other controlcircuitry or a human-machine-interface (not separately depicted).Additionally, the control and monitoring circuitry 18 may be included inthe switchgear 16 or directly coupled to the switchgear, for example,via a serial cable.

Furthermore, as depicted, the electric power input to the switchgear 16and output from the switchgear 16 may be monitored by sensors 22. Morespecifically, the sensors 22 may monitor (e.g., measure) thecharacteristics (e.g., voltage or current) of the electric power.Accordingly, the sensors 22 may include voltage sensors and currentsensors. These sensors may alternatively be modeled or calculated valuesdetermined based on other measurements (e.g., virtual sensors). Manyother sensors and input devices may be used, depending upon theparameters available and the application. Additionally, thecharacteristics of the electric power measured by the sensors 22 may becommunicated to the control and monitoring circuitry 18 and used as thebasis for algorithmic computation and generation of waveforms (e.g.,voltage waveforms or current waveforms) that depict the electric power.More specifically, the waveforms generated based on input the sensors 22monitoring the electric power input into the switchgear 16 may be usedto define the control of the switching devices, for example, by reducingelectrical arcing when the switching devices open or close. Thewaveforms generated based on the sensors 22 monitoring the electricpower output from the switchgear 16 and supplied to the load 14 may beused in a feedback loop to, for example, monitor conditions of the load14.

As described above, the switchgear 16 may connect and/or disconnectelectric power from various types of loads 14, such as an electric motor24 included in the motor system 26 depicted in FIG. 2. As depicted, theswitchgear 16 may connect and/or disconnect the power source 12 from theelectric motor 24, such as during startup and shut down. Additionally,as depicted, the switchgear 16 will typically include or function withprotection circuitry 28 and the actual switching circuitry 30 that makesand breaks connections between the power source and the motor windings.More specifically, the protection circuitry 28 may include fuses and/orcircuit breakers, and the switching circuitry 30 will typically includerelays, contactors, and/or solid-state switches (e.g., SCRs, MOSFETs,IGBTs, and/or GT0s), such as within specific types of assembledequipment (e.g., motor starters).

More specifically, the switching devices included in the protectioncircuitry 28 may disconnect the power source 12 from the electric motor24 when an overload, a short circuit condition, or any other unwantedcondition is detected. Such control may be based on the un-instructedoperation of the device (e.g., due to heating, detection of excessivecurrent, and/or internal fault), or the control and monitoring circuitry18 may instruct the switching devices (e.g., contactors or relays)included in the switching circuitry 30 to open or close. For example,the switching circuitry 30 may include one (e.g., a three-phasecontactor) or more contactors (e.g., three or more single-pole, singlecurrent-carrying path switching devices).

Accordingly, to start the electric motor 24, the control and monitoringcircuitry 18 may instruct the one or more contactors in the switchingcircuitry 30 to close individually, together, or in a sequential manner.On the other hand, to stop the electric motor 24, the control andmonitoring circuitry 18 may instruct the one or more contactors in theswitching circuitry 30 to open individually, together, or in asequential manner. When the one or more contactors are closed, electricpower from the power source 12 is connected to the electric motor 24 oradjusted and, when the one or more contactors are open, the electricpower is removed from the electric motor 24 or adjusted. Other circuitsin the system may provide controlled waveforms that regulate operationof the motor (e.g., motor drives, automation controllers, etc.), such asbased upon movement of articles or manufacture, pressures, temperatures,and so forth. Such control may be based on varying the frequency ofpower waveforms to produce a controlled speed of the motor.

In some embodiments, the control and monitoring circuitry 18 maydetermine when to open or close the one or more contactors based atleast in part on the characteristics of the electric power (e.g.,voltage, current, or frequency) measured by the sensors 22.Additionally, the control and monitoring circuitry 18 may receive aninstruction to open or close the one or more contactors in the switchingcircuitry 30 from another part of the motor system 26, for example, viathe network 21.

In addition to using the switchgear 16 to connect or disconnect electricpower directly from the electric motor 24, the switchgear 16 may connector disconnect electric power from a motor controller/drive 32 includedin a machine or process system 34. More specifically, the system 34includes a machine or process 36 that receives an input 38 and producesan output 40.

To facilitate producing the output 40, the machine or process 36 mayinclude various actuators (e.g., electric motors 24) and sensors 22. Asdepicted, one of the electric motors 24 is controlled by the motorcontroller/drive 32. More specifically, the motor controller/drive 32may control the velocity (e.g., linear and/or rotational), torque,and/or position of the electric motor 24. Accordingly, as used herein,the motor controller/drive 32 may include a motor starter (e.g., awye-delta starter), a soft starter, a motor drive (e.g., a frequencyconverter), a motor controller, or any other desired motor poweringdevice. Additionally, since the switchgear 16 may selectively connect ordisconnect electric power from the motor controller/drive 32, theswitchgear 16 may indirectly connect or disconnect electric power fromthe electric motor 24.

As used herein, the “switchgear/control circuitry” 42 is used togenerally refer to the switchgear 16 and the motor controller/drive 32.As depicted, the switchgear/control circuitry 42 is communicativelycoupled to a controller 44 (e.g., an automation controller. Morespecifically, the controller 44 may be a programmable logic controller(PLC) that locally (or remotely) controls operation of theswitchgear/control circuitry 42. For example, the controller 44 mayinstruct the motor controller/driver 32 regarding a desired velocity ofthe electric motor 24. Additionally, the controller 44 may instruct theswitchgear 16 to connect or disconnect electric power. Accordingly, thecontroller 44 may include one or more processor 45 and memory 46. Morespecifically, the memory 46 may be a tangible non-transitorycomputer-readable medium on which instructions are stored. As will bedescribed in more detail below, the computer-readable instructions maybe configured to perform various processes described when executed bythe one or more processor 45. In some embodiments, the controller 44 mayalso be included within the switchgear/control circuitry 42.

Furthermore, the controller 44 may be coupled to other parts of themachine or process system 34 via the network 21. For example, asdepicted, the controller 44 is coupled to the remote control andmonitoring circuitry 18 via the network 21. More specifically, theautomation controller 44 may receive instructions from the remotecontrol and monitoring circuitry 18 regarding control of theswitchgear/control circuitry 42. Additionally, the controller 44 maysend measurements or diagnostic information, such as the status of theelectric motor 24, to the remote control and monitoring circuitry 18. Inother words, the remote control and monitoring circuitry 18 may enable auser to control and monitor the machine or process 36 from a remotelocation.

Moreover, sensors 22 may be included throughout the machine or processsystem 34. More specifically, as depicted, sensors 22 may monitorelectric power supplied to the switchgear 16, electric power supplied tothe motor controller/drive 32, and electric power supplied to theelectric motor 24. Additionally, as depicted, sensors 22 may be includedto monitor the machine or process 36. For example, in a manufacturingprocess, sensors 22 may be included to measure speeds, torques, flowrates, pressures, the presence of items and components, or any otherparameters relevant to the controlled process or machine.

As described above, the sensors 22 may feedback information gatheredregarding the switchgear/control circuitry 42, the motor 24, and/or themachine or process 36 to the control and monitoring circuitry 18 in afeedback loop. More specifically, the sensors 22 may provide thegathered information to the automation controller 44 and the automationcontroller 44 may relay the information to the remote control andmonitoring circuitry 18. Additionally, the sensors 22 may provide thegathered information directly to the remote control and monitoringcircuitry 18, for example via the network 21.

To facilitate operation of the machine or process 36, the electric motor24 converts electric power to provide mechanical power. To helpillustrate, an electric motor 24 may provide mechanical power to variousdevices, as described below. For example, the electric motor 24 mayprovide mechanical power to a fan, a conveyer belt, a pump, a chillersystem, and various other types of loads that may benefit from theadvances proposed.

Point-on-Wave (POW) Switching

As discussed in the above examples, the switchgear/control circuitry 42may control operation of a load 14 (e.g., electric motor 24) bycontrolling electric power supplied to the load 14. For example,switching devices (e.g., contactors) in the switchgear/control circuitry42 may be closed to supply electric power to the load 14 and opened todisconnect electric power from the load 14. However, as discussed above,opening (e.g., breaking) and closing (e.g., making) the switchingdevices may discharge electric power in the form of electric arcing,cause current oscillations to be supplied to the load 14, and/or causethe load 14 to produce torque oscillations.

Accordingly, some embodiments of the present disclosure providetechniques for breaking a switching device in coordination with aspecific point on an electric power waveform. For example, to reducemagnitude and/or likelihood of arcing, the switching device may openbased on a current zero-crossing or any other desired point on of ananalog wave signal conducting through the respective switching device.As used herein, a “current zero-crossing” is intended to describe whenthe current conducted by the switching device is zero. Accordingly, bybreaking exactly at a current zero-crossing, the likelihood ofgenerating an arc is minimal since the conducted current is zero.

Although some embodiments describe breaking a switching device based ona current zero-crossing or making the switching device based on apredicted current zero-crossing, it should be understood that theswitching devices may be controlled to open and close at any desiredpoint on the waveform using the disclosed techniques. To facilitateopening and/or closing at a desired point on the waveform, one or moreswitching devices may be independently controlled to selectively connectand disconnect a phase of electric power to the load 14. In someembodiments, the one or more switching devices may be a multi-pole,multi-current carrying path switching device that controls connection ofeach phase with a separate pole. More specifically, the multi-pole,multi-current carrying path switching device may control each phase ofelectric power by movement of a common assembly under the influence of asingle operator (e.g., an electromagnetic operator). Thus, in someembodiments, to facilitate independent control, each pole may beconnected to the common assembly in an offset manner, thereby enablingmovement of the common assembly to affect one or more of the polesdifferently.

In other embodiments, the one or more switching devices may includemultiple single pole switching devices. As used herein a “single poleswitching device” is intended to differentiate from a multi-pole, multicurrent-carrying path switching device in that each phase is controlledby movement of a separate assembly under influence of a separateoperator. In some embodiments, the single pole switching device may be asingle pole, multi-current carrying path switching device (e.g.,multiple current carrying paths controlled by movement of a singleoperator) or a single-pole, single current-carrying path switchingdevice, which will be described in more detail below.

As described above, controlling the making (e.g., closing) of the one ormore switching devices may facilitate reducing magnitude of in-rushcurrent and/or current oscillations, which may strain the load 14, thepower source 12, and/or other connected components. As such, the one ormore switching devices may be controlled such that they make based atleast in part on a predicted current zero-crossing (e.g., within a rangeslightly before to slightly after the predicted current zero crossing).

Single-Pole, Single Current-Carrying Path Switching Device

FIGS. 4-6 depict a presently contemplated arrangement for providing asingle-pole, single current-carrying path switching device. The devicemay be used in single-phase applications, or very usefully inmulti-phase (e.g., three-phase) circuits. It may be used alone or toform modular devices and assemblies such as for specific purposes asdescribed below. Moreover, it may be designed for use in POW powerapplication, and in such applications, synergies may be realized thatallow for very compact and efficient designs due, as least in part, tothe reduced operator demands, reduced arcing, and improvedelectromagnetic effects during the application of current through thedevice.

It should be noted that various embodiments of the single-pole switchingdevices may be used in single current-carrying path applications andalso in multi current-carrying path applications. That is, references tosingle-pole switching devices throughout the disclosure may refer tosingle-pole, single current carrying path switching devices,single-pole, multiple current carrying path switching devices, or somecombination thereof. In some embodiments, a single-pole, multiplecurrent-carrying path switching device may allow for the repurposing ofcertain devices as modular three-phase circuits. For example, asingle-pole, multiple current-carrying path may refer to a switchingdevice with three current-carrying paths that have been interconnectedto provide a single phase of power. Additionally, in some embodiments,three single-pole, single current-carrying path switching devices mayeach be configured to provide a separate phase of power (e.g.,three-phase) and can be independently and/or simultaneously controlledin various beneficial configurations, as described in detail below. Itshould be understood, that the single-pole switching devices may bemodularly configured to provide any number of power phases.

FIG. 4 illustrates a switching device 82 designed for use in certain ofthe applications described in the present disclosure. In the embodimentillustrated, a switching device is a single-pole, singlecurrent-carrying path device in the form of a contactor 84. Thecontactor 84 generally includes an operator section 86 and a contactsection 88. As described more fully below, the operator section includescomponents that enable energization and de-energization of the contactorto complete and interrupt a single current-carrying path through thedevice. The section 88 includes components that are stationary and othercomponents that are moved by energization and de-energization of theoperator section to complete and interrupt the single-carrying path. Inthe illustrated embodiment, the upper conductive section has an upperhousing 90, while the operator section has a lower housing 92. Thehousings fit together to form a single unitary housing body. In theillustrated embodiment flanges 94 extend from the lower housing allowingthe device to be mounted in operation. Other mounting arrangements maycertainly be envisaged. A line-side conductor 96 extends from the deviceto enable connection to a source of power. A corresponding load-sideconductor 98 extends from an opposite side to enable the device to becoupled to a load. In other embodiments, conductors may exit the housing90 and 92 in other manners. In this illustrated embodiment the devicealso includes an upper or top-side auxiliary actuator 100 and a sidemount auxiliary actuator 102.

FIG. 5 illustrates certain of the mechanical, electrical and operationalcomponents of the contactor in an exploded view. As shown, the operatorsection is mounted in the lower housing 92 and includes an operatordesignated generally by reference numeral 104 which itself is acollection of components including a magnetic core comprised of a yoke106 and a central core section 108. A return spring 110 is mountedthrough the central core section 108 as described more fully below forbiasing movable contacts towards an open position. An operator coil 112is mounted around the core section 108 and between upturned portions ofthe yoke 106. As will be appreciated by those skilled in the art, thecoil 112 will typically be mounted on a bobbin and is formed of multipleturns of magnet wire, such as copper. The operator includes leads 114,which in this embodiment extend upwardly to enable connection to theoperator when the components are assembled in the device. As will alsobe appreciated by those skilled in the art, the core, including the yokeand central core section, along with the coil 112 form an electromagnetwhich, when energized, attracts one or more parts of the movable contactassembly described below, to shift the device between an open positionand a closed position.

A movable contact assembly 116 similarly includes a number of componentsassembled as a sub-assembly over the operator. In the embodimentillustrated in FIG. 8, the movable assembly includes an armature 118that is made of a metal or material that can be attracted by fluxgenerated by energization of the operator. The armature is attached to acarrier 120 which typically is made of a non-conductive material, suchas plastic or fiberglass, or any other suitable electrically insulatingmaterial. A conductor assembly 122 is mounted in the carrier and ismoved upwardly and downwardly by movement of the carrier under theinfluence of electromagnetic flux that draws the armature downwardly,and, when the fluxes are removed, the entire assembly may be movedupwardly under the influence of the return spring 110 mentioned above.

The device further includes a stationary contact assembly 124. In theillustrated embodiment, this contact assembly is formed of multiplehardware components, including a mounting assembly 126 that is fittedbetween the lower housing 92 and the upper housing 90. This mountingassembly will typically be made of an electrically non-conductivematerial, and it includes various features for allowing the mounting ofthe line and load-side conductors 96 and 98.

In some embodiments, the switching device may include a relay devicethat is composed of components illustrated in FIG. 6, some of whichcorrespond to the components of the switching device 82 described above.As shown in FIG. 6, relay device 140 may include an armature 142 that iscoupled to a spring 144. The armature 142 may have a common contact 146that may be coupled to a part of an electrical circuit. The armature 142may electrically couple the common contact 146 to a contact 148 or to acontact 150 depending on a state (e.g., energized) of the relay device140. For example, when a relay coil 152 of the relay device 140 is notenergized or does not receive voltage from a driving circuit, thearmature is positioned such that the common contact 146 and the contact148 are electrically coupled to each other. When the relay coil 152receives a driving voltage, the relay coil 152 magnetizes and attractsthe armature to itself, thereby connecting the contact 150 to the commoncontact 146.

Relay Coil Drive Circuit Using High Voltage and Constant Current

As mentioned above, the movement of the armature 142 causes a change inthe inductance of the relay coil 152, thereby making the change incurrent within the relay coil 152 to move in a nonlinear fashion. Forexample, FIG. 7 depicts a current-time graph 160 that illustrates thechange in current 162 within the relay coil 152 when a voltage isapplied to the relay coil 152 at time t0 and after the armature 142moves to close (e.g., curve 164) the relay device 140 at time t1. Asshown in FIG. 7, the current through the relay coil 152 increase in alinear fashion at time t0 but loses its linear property just before therelay device 140 closes at time t0. This nonlinear property of thecurrent conducting through the relay coil 152 is attributed to themovement of the armature 142 when the relay coil 152 magnetizes.

Since the current follows a nonlinear curve that changes due to theinductance of the relay coil 152, the time in which various relay coils152 having different inductances vary as well. For instance, FIG. 8illustrates a current-time graph 170 that illustrates the differences inthe amounts of times in which the relay coil 152 having differentinductances may reach its driving current when provided with a ratedvoltage. The rated voltage may correspond to a rating associated withthe relay coil 152. That is, the relay coil 152 may be rated for aparticular voltage to ensure that the relay coil 152 operateseffectively for a period of time and such that insulating features ofthe relay coil 152 are designed to withstand the rated voltage a numberof times before becoming inoperable.

Although the relay coil 152 may be rated for a particular voltage orvoltage range, in some embodiments, providing the relay coil 152 with avoltage that is higher than the rated voltage may reduce thediscrepancies between the amounts of time in which the each of thevarious relay coils having various inductances reaches its drivingcurrent. For example, FIG. 9 illustrates a current-time graph 180 thatillustrates the differences in the amounts of times in which the relaycoil 152 having different inductances may reach its driving current whenprovided with a voltage that is higher than the voltage rated for therelay coil 152. As mentioned above, by providing a higher voltage to therelay coil 152, as compared to the rated voltage, the variability of theamount of time in which different relay coils 152 having differentinductances may decrease. Indeed, as shown in the current-time graph180, by providing a 24V supply to relay coils 152 having differentinductances causes the time in which each relay coil 152 reaches itsdriving current to decrease, as compared to providing the 5V (e.g.,relay coil rating) supply to the relay coils 152 depicted in FIG. 8.

In some embodiments, the voltage provided to the relay coil 152 may bebetween four and five times the rated voltage of the relay coil 152.That is, since the relay coil 152 is rated for a particular voltage orvoltage range, providing a voltage supply that is higher than thevoltage rating of the relay coil 152 may reduce the life of the relaycoil 152 due to insulation breakdown and wear. However, by limiting thehigher voltage supply to four and five times the rated voltage of therelay coil 152, the present embodiments may limit the effects of wearingdown the relay coil 152. In any case, although the present embodimentsare described herein as using a voltage source that provides four tofive times the rated voltage of the relay coil 152 to the relay coil152, it should be understood that the embodiments described hereinshould not be limited to voltage supplies that are four to five timesthe rated voltage of the relay coil 152. Instead, any suitable voltagesupply may be used with the embodiments described herein.

With this in mind, it should be noted that the relatively higher voltagesupply provided to the relay coil 152 may be controlled in a manner thatlimits the exposure of the relay coil 152 to the higher voltage levelsfor a period of time that allows the relay coil 152 to reach its drivingcurrent. In some embodiments, two voltage sources may be used toenergize the relay coil 152, such that the relay coil 152 may receive arelatively higher voltage for a short period of time to allow the relaycoil 152 to reach its drive current. After the relay coil 152 isexpected to reach its drive current, one of the voltage sources may bedisconnected from the relay coil 152, while the other voltage sourceremains coupled to the relay coil 152 to provide a voltage that matchesthe voltage rating of the relay coil 15. For example, FIG. 10illustrates an example circuit 190 that includes a switch 192 thatcouples a voltage source 194 when initially driving the relay coil 152.The voltage source 194 may output a voltage that is higher than therating of the relay coil 152. After initially driving the relay coil152, a switch 195 may be closed and the switch 192 may be opened toconnect a voltage source 196 to the relay coil 152. The voltage source196 may output a voltage that corresponds to the rating of the relaycoil 152. In some embodiments, the voltage source 194 may provide therelay coil 152 with a voltage that corresponds to four to five times therated voltage of the relay coil 152.

The switch 192 and the switch 195 may be controlled by a control system,controller, or the like. In some embodiments, the control system may:(1) close the switch 192 and open the switch 195 in response to a signalindicating that the relay coil 152 is being energized; and (2) open theswitch 192 and close the switch 195 after the relay coil 152 is expectedto reach its driving current. After the relay coil 152 is expected toreach its driving current, the switch 195 may open and the switch 192may close, thereby allowing the voltage source 194 to keep the relaycoil 152 energized. In this way, the relatively high voltage applied tothe relay coil 152 may be provided for a limited amount of time topreserve the integrity and operability of the relay coil 152 over time.

In addition to coordinating the voltage applied to the relay coil 152,the circuit 190 may provide a constant current to the relay coil 152.Using a constant current source to energize the relay coil 152 mayprovide added benefits to the operation of the respective relay device.For example, providing a constant current to the relay coil 152 mayprovide for improved consistency in closing times and power efficiency,as compared to connecting a constant voltage source to the relay coil152, over a spectrum of relay coils 152 having different inductances,armature positions, and the like. Additional details with regard toemploying a constant current source to drive the relay coil 152 will bediscussed below.

Referring back to the circuit 190 of FIG. 10, by way of operation, acontrol system 198 may provide a gate signal to a switching device 200(e.g., transistor) to energize the relay coil 152. By providing the gatesignal to the switching device 200, the switching device 200 may closeand a current may be drawn through resistor 202 via the voltage source196. In some embodiments, a Zener diode 204 may be coupled between theresistor 202 and the voltage source 196. The Zener diode 204 may be asemiconductor device that permits current to flow in a forward orreverse direction. In addition, the Zener diode 204 may clamp or limitthe voltage provided to the resistor 202. When engaging the relay coil152, the control system 198 may send a signal to the switch 192 to closeat the same time (e.g., within microseconds) as a switching device 206closes based on the gate signal provided via a node 208 between theresistor 202 and the Zener diode 204. As discussed above, by initiallyconnecting the voltage source 194 and the voltage source 196 to therelay coil 152, the coil current may reach the drive current valuewithin a faster amount of time, as compared to just connecting thevoltage source 196. In some embodiments, after the amount of time thatthe relay coil 152 is expected to reach the drive current value, thecontrol system 198 may send a command to the switch 192 causing theswitch 192 to open, thereby connecting the relay coil 152 to just thevoltage source 196. As mentioned above, the voltage source 196 mayprovide a voltage that matches the rated voltage of the relay coil 152.By disconnecting the additional voltage source 194 from the relay coil152 after a limited amount of time, the present embodiments may preservethe life of the relay coil 152 while achieving a consistent close time.

Referring back to the Zener diode 204 of FIG. 10, in some embodiments,the Zener diode 204 may be selected or sized to match or offsettemperature characteristics of the switching device 206. That is, theswitching device 206 may have a base-to-emitter temperature coefficientthat indicates how the properties (e.g., voltage) of the switchingdevice 206 changes with respect to temperature. To prevent temperaturefrom influencing the operation of the relay coil 152, the Zener diode204 may be selected to have temperature properties that offset those ofthe switching device 206. For example, the switching device 206 may havea base-to-emitter temperature coefficient that indicates that thebase-to-emitter voltage changes −1.3 mV for each degree Celsius. Assuch, the Zener diode 204 may be selected to have a voltage that changes+1.3 mV for each degree Celsius to offset the effects due to theswitching device 206.

It should be noted that the control system 198 may include any suitablecomputing system, controller, or the like. As such, the control system198 may include a communication component, a processor, a memory, astorage, input/output (I/O) ports, a display, and the like. Thecommunication component may be a wireless or wired communicationcomponent that may facilitate communication between different componentswithin the industrial automation system, the relay device 140, or thelike.

The processor may be any type of computer processor or microprocessorcapable of executing computer-executable code. The processor may alsoinclude multiple processors that may perform the operations describedbelow. The memory and the storage may be any suitable articles ofmanufacture that can serve as media to store processor-executable code,data, or the like. These articles of manufacture may representcomputer-readable media (e.g., any suitable form of memory or storage)that may store the processor-executable code used by the processor toperform the presently disclosed techniques. The memory and the storagemay represent non-transitory computer-readable media (e.g., any suitableform of memory or storage) that may store the processor-executable codeused by the processor to perform various techniques described herein. Itshould be noted that non-transitory merely indicates that the media istangible and not a signal.

The I/O ports may be interfaces that may couple to other peripheralcomponents such as input devices (e.g., keyboard, mouse), sensors,input/output (I/O) modules, and the like. The display may operate todepict visualizations associated with software or executable code beingprocessed by the processor. In one embodiment, the display may be atouch display capable of receiving inputs from a user. The display maybe any suitable type of display, such as a liquid crystal display (LCD),plasma display, or an organic light emitting diode (OLED) display, forexample. Additionally, in one embodiment, the display may be provided inconjunction with a touch-sensitive mechanism (e.g., a touch screen) thatmay function as part of a control interface. It should be noted that thecomponents described above with regard to the control system 198 areexemplary components and the control system 198 may include additionalor fewer components as shown.

Referring back to FIG. 10, it should be appreciated that the circuit 190described above may be employed in a number of ways. That is, in oneembodiment, the relay coil 152 may be provided with a constant currentusing a high voltage source (e.g., voltage source 194 and voltage source196). Alternatively, the relay coil 152 may be provided with a constantcurrent using a voltage source (e.g., voltage source 196) thatcorresponds to the rating of the relay coil 152. In either case, using aconstant current source to drive the relay coil 152 may provide a numberof benefits as will be detailed below.

For example, FIG. 11 illustrates a current-time graph 220 that depictshow the current within the relay coil 152 may change over time when therelay coil 152 is driven at time t0 using a constant voltage (e.g.,curve 222) and using a constant current (e.g., curve 224). As shown inFIG. 11, at time t0, the current within the relay coil 152 reaches asteady state value within ˜0.5 ms when the relay coil 152 is drivenusing the constant current (e.g., curve 224). Moreover, the current inthe relay coil 152 changes in a nonlinear fashion when the relay coil152 is driven using the constant voltage (e.g., curve 222). Thenonlinear nature of the current in the relay coil 152 may cause therelay coil 152 to energize at inconsistent times, thereby causing therespective relay device to close inconsistently across a variety ofinductances and armature positions.

In addition to reaching the driving current within the relay coil 152according to a linear function, using the constant current source todrive the relay coil 152 may also enable the relay device to have aconsistent movement profile for the armature 142 over a variety of coilresistances. For example, FIG. 12 illustrates a position-time graph 230that depicts how the position of the armature 142 may change over timewhen the relay coil 152 is driven with a constant current source versusa constant voltage source. Referring to FIG. 12, curve 232 correspondsto the movement profile of the armature 142 over time when the relaycoil 152 is driven with a constant current source for a variety of relaycoils 152 having a variety of resistances. That is, the curve 232represents a number of movement profiles for a number of relay coils152. One curve 232 is visible in the position-time graph 230 because therespective movement profile curve for each different relay coil 152having a different resistance is overlaid on top of each other due tothe similarities in the respective movement profiles. In contrast, thecurves 232 correspond to movement profiles of the armature 142 over timewhen the relay coil 152 is driven with a constant voltage source for avariety of relay coils 152 having a variety of resistances. As depictedwith the curves 234, the movement profile of the armature 142 variessignificantly based on the various resistances of the relay coil 152when the relay coil 152 is driven with a constant voltage source, ascompared to a constant current source (e.g., curve 232).

Driving the relay coil 152 using a constant current source may alsoenable the armature 142 to close more consistently across variousinductances of the relay coil 152 when the relay coil 152 is driven witha similar current value. For instance, FIG. 13 illustrates aninductance-current graph 240 that indicates the coil current values thatcause various relay coils 152 having various inductances to close whenthe relay coil 152 is driven with a constant current source versus aconstant voltage source. Referring to FIG. 13, curve 242 traces when therelay coil 152 closes when driven with a constant current for a varietyof relay coils 152 having a variety of inductance values. As shown inthe graph 240, when the relay coil 152 is driven with the constantcurrent source, the armature 142 closes at approximately the same time(e.g., t1). In contrast, the curve 244 traces the current values in thevariety of relay coils 152 when the relay coils 152 close and when therelay coils 152 are driven with a constant voltage source. As made clearin the graph 240, the current values in the relay coil 152 thatcorrespond to when the armature 142 closes vary greatly with respect tothe inductance of the relay coil 152 when the relay coil 152 is drivenwith a constant voltage source, as compared to being driven with aconstant current source.

The constant current source also enables the relay device to preservemore energy and operate the relay coil 152 more efficiently. FIG. 14illustrates a current-time graph 250 that depicts the energy waste inthe relay coil 152 when the relay coil 152 is driven with a constantcurrent (e.g., curve 252) versus a constant voltage (e.g., curves 254).As shown in FIG. 14, the curve 252 remains consistent for a number ofresistances of the relay coil 152, whereas the curves 254 varies as theresistances of the relay coil 152 varies. In addition, it is clear fromthe graph 250 that driving the relay coil 152 using the constant voltagesource (e.g., curves 254) results in the relay coil 152 conducting morecurrent as compared to when the relay coil 152 is driven with a constantcurrent source (e.g., curve 252). The difference in the current betweenthe two sources of power result in a certain amount of energy waste inthe relay coil 152.

Indeed, the constant current source automatically adjusts the voltage ofthe relay coil 152 over time to maintain a consistent operation of thearmature 142. To illustrate this, FIG. 15 illustrates a voltage-timegraph 260 that depicts the voltage change in the relay coil 152 when therelay coil 152 is driven with a constant voltage source (e.g., curve266) versus a constant current source (e.g., curves 268). As shown inFIG. 15, the curve 266 remains at a particular voltage level for anumber of resistances of the relay coil 152, whereas the curves 268detail how the constant current source automatically adjusts the voltageof the relay coil 152 across various resistances of the relay coil 152.In this way, the voltage of the relay coil 152 maintains consistentoperation with the current source.

With the foregoing in mind, technical effects of the present embodimentsinclude enabling POW switching to perform more consistently over varioustypes of relay coils having various inductances, resistances, and thelike. When switching devices are manufactured, a number of variables maycause the coil of a switching device to differ from other coilsmanufactured using the same process or in the same facility. To ensurethat the switching device opens and closes according to a consistent andexpected fashion, the coils may be driven using a constant currentsource. In some embodiments, the constant current source may befacilitated by a voltage source that outputs a voltage that is higherthan the rated voltage of the respective coil. As a result, theswitching devices may close at more consistent and predictable timeintervals, while preserving energy and operating more efficiently.

Controlling Contact Bounce

In some embodiments, relay devices and contactor devices operate suchthat they are normally open or normally closed when the relay coil 152is not energized. That is, normally open relay devices may includecontacts or the armature 142 that is open or not electrically connectingtwo electrical nodes when relay coil 152 is not energized. In the samemanner, normally closed relay devices may include contacts or thearmature 142 that is open when the relay coil 152 is not energized. Assuch, when attempting to close or open during a respective POW close orPOW open command, the respective relay device may have a number ofvariables, such as the magnetic properties in an air gap between thearmature 142 and the relay coil 152 or between contacts of the contactor84. That is, for example, when energizing a respective coil, a number ofmagnetic factors begin to affect the operation of the respective relaydevice or contactor. These magnetic factors may cause the respectivedevice to act inconsistently, thereby reducing the accuracy of the POWswitching. In addition, by energizing the respective coil to open orclose the respective relay device or contactor under these variableconditions, the amount of times that the contacts close due to bouncingmay increase, thereby resulting in a reduced life of the contacts.Indeed, since the coil has energy when the contactor closes or opens,the energy may dissipate across the relay and contacts, therebyincreasing the wear on the relay.

Keeping this in mind, in some embodiments, POW switching may be employedto minimize the arc energy available across contacts when the respectivedevice opens or closes. For example, if the contact is closed where thecorresponding voltage signal is near its peak, the available arc energymay be relatively higher as compared to closing the contact when thevoltage signal is near or approaching zero. Since the available arcenergy is related to the amount of voltage and current available overtime, the close timing can be coordinated to close when the availablearc energy is expected to be the lowest. The arc energy is a significantfactor is wearing out the contacts. That is, the arc energy is providingthe high temperature event that wears down the material of the contacteach time the contacts close or bounce against each other.

At times, coordinating the timing for a relay device or any othersuitable switching device to open and close within a threshold amount oftime with respect a zero-voltage crossing may not be practical. Forinstance, upon detection of a fault, a relay device may immediately openor close with regard to the voltage waveform present on the respectivecontacts. As a result, when the armature 142 moves and one contact movesto physically couple with another contact, the amount of available arcenergy may not be minimized because the point on the voltage waveform inwhich the armature 142 moves may not be near the zero-crossing. Inaddition, depending on the number times that the contacts bounce againsteach other, additional opportunities for electrical arcing are present.Moreover, the number of bounces between the contacts under the variousarcing conditions may be directly related to the wear on the contacts,and thus the relay device. Accordingly, to increase the life of thecontacts and the relay device, the number of contact bounces between thecontacts should be minimized.

Keeping this in mind, to reduce the number of contact bounces, in someembodiments, the speed in which the armature 142 of the relay device 140(e.g., FIG. 6) moves may control the number of bounces that the contactsmay occur during a close or open operation. That is, referring brieflyagain to FIG. 6, the speed in which the armature 142 moves from positionA to position B may directly affect the number of times that contact 262may bounce against contact 264. Since the contact 262 is electricallycharged with some voltage, the bounces between the contact 262 and thecontact 264 may result in electrical arcing that may wear down theconductive material (e.g., copper) that makes up the contact 262 and thecontact 264.

Since the armature 142 controls the position of the contact 262 and thecontact 264, it may be useful to reduce a speed of the armature 142 whenit moves between positions A and B. That is, by reducing the speed inwhich the armature 142 moves between positions A and B, the kineticenergy dissipated through the bounces of the contacts 262 and 264 may bereduced, thereby reducing the total number of bounces that occur betweenthe contacts 262 and 264.

FIG. 16 illustrates an example position-time graph 270 that depicts aposition of the armature 142 over time when the armature 142 closes witha first velocity (e.g., curve 272), as compared to when the armature 142closes with a second velocity slower than the first velocity (e.g.,curve 274). The high velocity movement of the armature 142 characterizedby the curve 272 causes a relatively high impact energy since kineticenergy (KE) is defined as a function of velocity (v) and mass (m), asshown in Equation 2 below.

KE=1/2mv²   (2)

In contrast the impact energy available to the armature 142 that movesaccording to the curve 272, the armature 142 that moves in accordance tothe curve 274 may have a smaller velocity and thus less impact energyavailable to contributed to contact bounce. To enable the armature 142to reduce its speed during some operation (e.g., close), a controlcircuit may introduce or electrically couple an external inductance tothe relay coil 152 at a time that is within some threshold period oftime before the armature 142 moves between positions A and B. In someembodiments, the external inductance may be approximately one order ofmagnitude larger than the inductance of the relay coil 152 to overcomethe momentum of the movement of the armature 142, such that the speed inwhich the armature 142 reduces within a threshold amount of time beforethe contacts 262 and 264 physically touch each other.

FIG. 17 illustrates an example circuit 280 that may be employed to addexternal inductance to the relay coil 152 in accordance with theembodiments described herein. Referring to FIG. 17, the circuit 280 maybe similar the circuit 190 described above with respect to FIG. 10. Thecircuit 280 includes additional circuitry 282 that inserts an additionalinductor 284 in series with the relay coil 152 when the relay device 140is opening or closing. The additional inductance may cause the armature142 to reduce in speed, thereby reducing the amount of impact energyavailable to the contacts 262 and 264, such that the number of bouncesbetween the contacts 262 and 264 are minimal.

By way of operation, the control system 198 may send a gate signal to aswitching device 286 while the relay device 140 is in its normaloperating condition (e.g., normally open, normally closed). That is,when the relay coil 152 is not energized, for example, the controlsystem 198 may send a gate signal to the switching device 286 to causethe switching device 286 to close and couple the relay coil 152 toground. After detecting that the relay coil 152 will be energized (e.g.,in response to a signal/fault), the control system 198 may remove thegate signal provided to the switching device 286, thereby causing theswitching device 286 to open. As such, the additional inductor 284 maybe connected in series with the relay coil 152 to increase the effectiveinductance of the relay device 140 after the relay coil 152 isenergized. As a result, the added inductance sharply decreases the coilcurrent of the relay coil 152 when switched in, and then creates asecond total inductance that should be re-energized. The sharp decreasein coil current momentarily decreases the armature force, as well asslows the rise time of the armature force, allowing for a soft close. Inother words, the movement of the armature 142 decreases due to sharpdecrease in the coil current, thereby causing the armature 142 to reduceits speed as shown in the curve 274 of FIG. 16.

With this in mind, depending on the size of the relay coil 152, it maybe challenging to incorporate the additional inductor 284 into the relaydevice 140. That is, the additional inductor 284 may cause magneticinterference with other circuit components or the relay device 140 maynot be large enough to physically include the additional inductor 284.As such, in some embodiments, the control system 198 may pulse a currentto the relay coil 152 to achieve an optimal armature position profilethat may reduce the speed of the movement of the armature 142. Thepulsing current may enable the relay device 140 to reduce the speed inwhich the armature 142 operates without including the additionalinductor 284 in the circuit 280. That is, an initial coil current thatcauses the armature 142 to move may be provided to the relay coil 152.In some embodiments, before the relay device 140 is expected to close,the control system 198 may remove the current provided to the relay coil152, and the momentum of the armature 142 may decrease due to the lossof current to the relay coil 152. After the armature 142 moves to coupletwo contacts (e.g., contacts 262 and 264), the control system 198 mayagain provide the current to the relay coil 152.

FIG. 18 illustrates a current-time graph 300 that depicts an embodimentin which a pulsed coil current is provided to the relay coil 152. Asshown in FIG. 18, the current is provided to the relay coil 152 for afirst duration of time (e.g., T(ON1), the current is removed for asecond duration of time (e.g., T(OFF)), and the current is returned fora third duration of time (e.g., T(ON2)). The third duration of time maycorrespond to keeping the relay coil 152 energized. FIG. 19 illustratesa pulsed coil current graph 310 that includes a coil curve 312 thatrepresents a pulsed current provided to the relay coil 152. The pulsedcoil current graph 310 also includes an armature position curve 314 thatillustrates a movement profile of the armature 142 over time. As shownin FIG. 19, the slope of the armature position curve 314 is altered whenthe current is removed from the relay coil 152 at time T0. At time T1,the current is provided again to the relay coil 152, thereby causing theslope of the armature position curve 314 to increase again. However,since the slope of the armature position curve 314 decreased betweentimes T0 and T1, the armature 142 slowly changes positions (e.g., fromposition A to B) until time T2. That is, the armature 142 is stillmoving slightly between times T0 and T1. The contacts change state afterthe armature position curve 314 crosses the horizontal line depicted inFIG. 19. As such, the armature 142 begins to slow down before thecontacts change state until time T2 when the armature 142 is fullyclosed. In this way, the contacts close before the armature 142 closes(e.g., over travel). However, the kinetic energy associated with themovement of the armature 142 decreases between T0 and T1 to decreaseimpact energy when the contacts change state. As such, the speed of thearmature 142 decreases before changing positions, thereby reducing theimpact energy provided by the armature 142 when the contacts 262 and 264physically touch each other.

Although the embodiments described above are detailed in accordance withan open loop system based on expected behavior or properties for variousvariables (e.g., armature speed), it should be noted that the operationof the various techniques described herein could be implemented in aclosed-loop system with position measurement on the armature 142,current/voltage data (e.g., via sensors) to glean additionalinformation, or the like. That is, different types of technology can beused to determine the positions of the armature 142, the contacts262/264, or the like. In addition, the measured inductance of the relaycoil 152 may be used to detect how fast the current changes with respectto voltage to determine characteristics of the position of the armature142. The inductance of the relay coil 152 may also be used to providesome self-monitoring operations to detect a failure (e.g., a weldedcontact). In this way, the measurement would be made based on a voltageapplied to the relay coil 152 and a measurement of the current on therelay coil 152 to determine the inductance, which may then be used todetermine whether the contacts 262/264 or relay device 140 is operatingcorrectly. If an error is detected, the control system 198 mayannunciate an alarm, disable the relay device 140, or the like.

In some embodiments, the properties (e.g., speed, close time) of thearmature 142 changes over time. To maintain the movement profile of thearmature 142 to minimize the impact energy between the contacts 262 and264, the control system 198 may monitor certain properties associatedwith the movement of the armature 142 as feedback to adjust the time inwhich a current pulse is applied, the additional inductor 284 is addedto the relay coil 152, or the like. For example, the control system 198may monitor the position of the armature 142 over time for each closeoperation, the voltage applied to the relay coil 152, the currentapplied to the relay coil 152, and other variables may be monitored viasensors (e.g., current sensor, voltage sensor) or other suitablemonitoring equipment. Although the closed loop system is describedherein is provided in the context of controlling a bounce of a contact,it should be noted that the closed loop system may be employed in anysuitable aspect of opening and closing (e.g., timing, speed) of the POWswitch.

As mentioned above, a constant current pulse may minimize or reduce thenumber of bounces between the contacts 262 and 264. It should also benoted that operating the relay device 140 using the current pulsedescribed above does not change the bounce characteristics of thecontacts 262 and 264 over different temperature ranges. As such, thepulsed coil embodiment may be agnostic to temperature changes within therelay device 140. It should again be noted that the various embodimentsdescribed herein may also be applied to contactors. That is, as morecontactors use direct current (DC) coils, the systems and methodsdescribed herein may better manage the power consumption of thecontactors and reduce the use of interposing relays in contactors.

Technical effects of the embodiments described herein controlling thevelocity of the armature using constant current pulses and/or anadditional external inductor. In some embodiments, the current pulsesmay be applied according a desired point on a voltage waveform presenton a contactor of the armature. The desired point on wave should be nearthe zero crossing to minimize the area underneath the voltage waveform,thereby reducing the available arc energy. However, it should be notedthat, in some embodiments, the relay device can switch at any point ofthe AC waveform with minimal arc energy (i.e., not just the zero crossof voltage).

De-Energize Relays for Point-on-Wave (POW) Close and Open Operations

Normally open relays include a contactor or a switch that is open whenthe coil of the relay is not energized. In the same manner, normallyclosed relays include contacts or a contactor or switch that is openwhen the coil of the relay is not energized. As such, when attempting toclose or open during a respective POW close or POW open command, therespective relay is influenced by a number of variables, such as themagnetic properties between the contacts of the contactor within the airgap. Thus, when energizing the coil, a number of magnetic factors beginto affect the operation of the respective relay. These magnetic factorsmay cause the relay to act inconsistently, thereby reducing the accuracyof the POW switching. In addition, by energizing the relay's coil toopen or close the respective switch, contact bounce may increase,resulting in a reduced life of the contacts. Indeed, since the coil hasenergy when the contactor closes or opens, the energy may dissipateacross the relay and contacts, thereby increasing the wear on the relay.

With this in mind, the contacts and the relays may benefit fromoperating in a manner such that the POW close or open operation occursby de-energizing a relay. FIG. 20 illustrates a process 330 implementedon specialized circuitry 332, which may be employed to control POW closeand open operations by de-energizing operations, in accordance with anembodiment. For simplicity, the process 330 and the associated states(334A, 334B, 334C, 334D, and 334E) of the specialized circuitry 332 willbe discussed together.

As illustrated, the specialized circuitry 332 includes a normally opencontact 336 connected in series with a normally closed contact 338.State 334A illustrates the normal state of the specialized circuitry332, where neither the normally open contact 336 nor the normally closedcontact 338 are energized. In state 334A, the normally open contact 336breaks the connection.

Next, process 330 begins to enable de-energized triggering of POW openand POW close operations. As mentioned above, triggering POW open andPOW close operations via de-energizing triggers rather than energizingtriggers may help to reduce variations that cause inconsistent POW openand/or POW close operations. For example, by performing the POW open andclose operations in this de-energizing fashion, the rate of magneticfield collapse may be the primary variable of control as opposed to anenergizing operation to perform the POW open and close operations, whichmay introduce inconsistent operations that are affected by the magneticproperties that are present within the air gap between the contacts, theenergy stored in the coil, and the like.

The process 330 begins with initialization (block 340) of thespecialized circuitry 332 into an energized state. In particular, theinitialization (block 340) includes energizing the normally closedcontact 338 (block 342). As illustrated by dashed line 344 in state334B, the normally closed contact 338 is energized, causing the normallyclosed contact 338 to open.

Next, the initialization (block 340) continues with energizing thenormally open contact (block 346). As illustrated by dashed line 348 instate 334C, the normally open contact 336 is energized, causing thenormally pen contact to close. As may be appreciated, because thenormally closed contact 338 was energized before the normally opencontact 336, the circuit is still broken by the normally closed contact338, despite closing of the normally open contact 336.

Upon energizing of both the normally open contact 336 and the normallyclosed contact 338, the initialization (block 340) is complete. Thus, areliable POW open operation and/or POW close operation may befacilitated via de-energizing one or more of the contacts of thespecialized circuitry.

For example, to perform a POW close operation 350, the normally closedcontact may be de-energized (block 352). As illustrated by the block 352in state 334D, the normally closed contact 338 is de-energized, causingit to close and completing the circuit. Thus, the POW close operation isimplemented by de-energizing a contact, which may improve consistency ofthe POW close operation, by reducing variables that may cause timingvariations in closing the circuit.

Conversely, when a POW open operation 354 is to be performed, thenormally open contact 336 may be de-energized (block 356). Asillustrated by the cross box 358 in state 334E, the normally opencontact 336 is de-energized, causing the normally open contact 336 toopen and also causing implementation of the POW open operation 354(e.g., by causing the closed circuit to break). As with thede-energizing triggering of the POW open operation, the de-energizingtriggering of the POW close operation may provide similar benefits ofreducing variables that may cause timing variations in implementation ofthe POW open operation.

As mentioned herein, arcing can sometimes occur between contacts. Thismay result in inconsistent POW open and POW close operations and canalso damage the contacts. Accordingly, it may be desirable to implementadditional arcing mitigation circuitry. FIG. 21 illustrates an examplecircuit 360 that implements arcing mitigation circuitry 362, inaccordance with an embodiment.

As illustrated, a triode for alternating current (TRIAC) device 364 maybe connected in parallel with contacts 366 of a relay on one or morephases of the circuit 360. Here, the TRIAC device 364 is implemented ona phase (e.g., Phase C 368) that will be the last phase to connect tothe load and, thus, the most likely to experience contact arcing. As maybe appreciated, the TRIAC device 364 can conduct current in eitherdirection when triggered. Here, the TRIAC device 364 is used to absorbarcing energy that is provided to the contacts 366, by redirecting aportion of the current applied current away from the contacts 366. Thisabsorption of arcing energy acts to protect the contacts 366 fromarcing. In addition, the arrangement of the parallel TRIAC with the POWcontact can be used as a cost-effective or simple starting torquecontroller (STC) or soft starter. Starting Torque Controllers helpreduce mechanical and electrical stress on motor circuits and systems bylimiting the torque surge at start-up. Starting torque controllers areideal for adding on to existing across the line starters. They allow foradjustable initial torque and ramp time.

The other phases (Phase A 370 and Phase B 372) may or may not include asimilar TRIAC device 364, depending on arcing mitigation needs for thecircuit 360. In the current example, these phases do not include a TRIACdevice 364, which may help reduce costs but may not provide the samelevel of arcing mitigation as embodiments that implement TRIAC devices364 on one or more of these phases.

Phase A 370 may be provided via a normally open contact 374. Phase B 372may be provided via a normally open contact or, as illustrated here, anormally open contact 376 in series with a normally closed contact 378.By way of operation, the contact in Phase A 370 may close to avoid anypotential arcing because the current is not yet present on the phase. Acoordinated close operation may be performed on Phase B 372 using POWswitching (e.g., as discussed above in reference to FIG. 20). Phase C368 may be connected through the TRIAC device 364, as discussed above.In some embodiments, the normally open contact 366 may be a multi-poledevice shared between Phase A 370 and Phase C 368, while the TRIACdevice 364 is closed.

In some embodiments, double-pole single-throw relays can be used tominimize the amount of times that a particular contact is used whenmaking a circuit connection. This may help in load balancing ofoperations on contacts, which may extend the life of the contacts.Further, these techniques may provide added connection redundancy, whichmay further enhance the circuitry. FIGS. 22 and 23 illustrate suchexample circuitry, in accordance with an embodiment.

In the circuitry 390 of FIG. 22 and the circuitry 390′ of FIG. 23, PhaseC may be alternatingly connected to the load via different relays (e.g.,relay 394 and relay 396). For example, Phase C may be alternatinglyconnected to the load via relays 394 and 396 when the contacts 398 and400 are alternatingly closed. This effectively reduces the number ofoperations sustained by contacts 398 and 400 by half. Thus, the contacts398 and 400 may wear less quickly. Further, this configuration providesadditional functional safety by providing redundant connections to theload (e.g., via contact 398 and contact 400). In some embodiments, asdepicted in FIG. 22, an additional relay 402 may be provided to connectPhase A and Phase C to the load. Alternatively, as depicted in FIG. 23,other embodiments may not include the additional relay 402. By employingthe two-relay circuity 390′ configuration of FIG. 23 as opposed to thethree-relay circuitry 390′ configuration of FIG. 22, the final productmay include less driver components and physical components, therebyreducing the cost and complexity of the device.

Contact Relay Reduction

In some instances, it may be desirable to reduce a number of contactelements provided in a relay. This may reduce manufacturing costs andprovide a simpler relay design. FIG. 24 illustrates an examplethree-phase relay circuit 410 which uses POW techniques to providereliable operation with a reduced number of contacts, in accordance withan embodiment. In the three-phase relay circuit 410, three poles, P1412, P2 414, and P3 416 are connected to load 418. Contact relays/breaks420A-F may be used to implement the POW techniques described herein. Ina standard implementation, six contact relays/breaks 420A-F may beprovided to implement these POW techniques. However, as mentionedherein, in some embodiments, it may be desirable to reduce and/orminimize the number of contact relay/breaks 420.

In the embodiment depicted in FIG. 24, the number of contactrelays/breaks 420A-F may be reduced from 6 to 4 (e.g., contactrelays/breaks 420A-D), as illustrated by dashed line contactrelays/breaks 420 E and 420F. It may be possible to reduce the number ofcontact relays/breaks 420A-F from 6 to 3 (e.g., contact relays/breaks420A, 420B, 420D) with 420C becoming a dashed line connection similar to420E/420F. Despite this reduction in contact relays/breaks 420, arcingmitigation can still be performed by adjusting opening/closing timingsof the relays/breaks 420 between the different poles P1 412, P2 414, andP3 416, as will be described in more detail below.

In some embodiments, the relay/break 420 that is opened can be toggledbetween contact relays/breaks 420 that are likely to experience a faultor arc. Different opening patterns may be employed for each faultoperation, which may help mitigate arcing effects. In other words,subsequent open operations can utilize different relay/breaks 420 toinitiate toe open operation. This will be discussed in more detail belowwith regard to FIGS. 25 and 26.

In the embodiment of FIG. 24, the three-phase relay circuit 410 has onefully equipped pole (e.g., pole with two contact relay/breaks 420 (e.g.,420B and 420C)), P2 414. The other two poles, P1 412 and P2 416 eachinclude a reduced number of contact relay/breaks 420. For example, poleP1 412 has been reduced to not include contact relay/break 420E and poleP3 has been reduced to not include contact relay/break 420F.

As may be appreciated, reducing the number of contact relay/breaks 420on a pole may remove some re-strike mitigation, by relying on a singlecontact relay/break 420. Accordingly, it may be desirable to leadopening/breaking with the fully equipped pole (e.g. pole P2 414). Byleading opening/breaking via fully equipped poles (e.g., pole P2 414),restrike mitigation may still be maintained for the contact relay/breaks420 that are most likely to arc/re-strike (e.g., contact relay/breaks420B and 420C) on the first-broken pole P2 414). After breaking thefully equipped poles, the other poles (e.g. poles P1 412 and P3 416) maybe opened.

In other words, for opening operations/breaking a connection to a load,poles with an increased number of contact relay/breaks 420 may be openedprior to opening poles with a reduced number of contact relay/breaks420. Thus, in the current embodiment, pole P2 414 may be opened prior topoles P1 412 and 43 416 during opening operations. This may be done byopening contact relay/breaks 420B and/or 420C.

Conversely, when connecting to a load, the poles with the reduced numberof contact relay/breaks 420 may be closed first, followed by the poleshaving the increased number of contact relay/breaks 420. Thus, in thecurrent embodiment, to make connection to the load 418, poles P1 412 andP3 416 may be closed first (e.g., by switching contact relay/breaks 420Aand 420D, respectively). Then, after these poles are connected, thepoles with the increased number of contact relay/breaks 420 may beconnected. Thus, in the current embodiment, P2 414 may be closed (e.g.,by switching contact relay/breaks 420B and 420C).

This delayed opening/closing time technique can be performed for POW aswell as non-POW devices. For non-POW devices, the timing delay betweenthe early break of the contact relay/breaks 420 on the pole(s) with theincreased number of contact relay/breaks 420 and the later break of thecontact relay/breaks 420 on the pole(s) with the reduced number ofcontact relay/breaks 420 should be at least a half cycle delay. For POWthe time delay can be reduced to a quarter cycle, as more preciseopening/closing may be possible.

Breaking capacity may be primarily dependent on contact gap in themoment of current zero cross for a switching device without anyadditional arc quenching. As mentioned above, coil control may be usedto provide ideal contact gap and therefore best arc cooling conditionsin the moment of current zero crossing. As described above, this couldbe done through pulsed coil control. This may increase an energy storagerequirement, but some of this may be mitigated by enabling this featureonly on the early break poles of a POW device.

As discussed above, arcing may occur with the contact relay/breaks 420that initially break or make connections to a load. To further mitigatecontact erosion, the order of opening and/or closing the contactrelay/breaks 420 and/or poles may be alternated.

For making connections to the load 418, the poles with the increasednumber of contact relay/breaks 420 is closed after the poles with thefewer number of contact relay/breaks 420. The order of closing the poleswith the fewer contact relay/breaks 420 may alternate. Thus, in thecurrent embodiment, switching the contact relay/breaks 420A and 420D mayinterchangeably initiate the connection. The initial contact relay/breakwill not be prone to arcing. The other of the contact relay/breaks 420Aand 420D may then be switched, which may have some possibility ofarcing. By alternating the order of switching of 420A and 420D, thepossibly arcing contact relay/break 420 may be shared, reducing contacterosion. After that, the pole with the increased number of contactrelay/breaks 420 (e.g., P2 414) may be closed by, switching contactrelay/breaks 420B and 420C alternatingly. This may cause distribution ofthe potentially arcing contact relay/break 420 (e.g., the last contactrelay/break 420 to connect to the load 418).

For breaking a connection to the load 418, the poles with the increasednumber of contact relay/breaks 420 will be opened first, as this polemay be better equipped to handle arcing/re-strikes. The order in whichthe contact relay/breaks 420 on these poles are opened can be alternatedto alleviate arcing on a particular one of the contact relay/breaks 420.Thus, in the current embodiment, for break sequences, contactrelay/breaks 420B and 420C of pole P2 414 may alternatingly initiate thebreaking procedure. From there, the other of relay/breaks 420B and 420Cmay be opened.

Next, the remaining poles may be opened in an alternating order. Thus,in the current embodiment poles P1 412 and P3 416 may be open in analternating order, by alternating the order of opening contactrelay/breaks 420A and 420D. This may help mitigate arcing caused by oneof these contact relay/breaks 420 A and 420 breaking the current.

In some embodiments, there may be an equal number of contactrelay/breaks 420 on all poles and each of these may be coordinated tostart and stop operations on a connected load, such that the load isdistributed across each pole. FIGS. 25 and 26 illustrate processes andassociated circuitry states for such embodiments.

FIG. 25 illustrates a process 440 for a first close operation to connectto a load. As illustrated, states of a three-pole circuitry 442 isprovided. In a first state 442A, all relays are open, as a stopped stateis present (block 444).

Next, a start command is provided (block 446). As illustrated in state442B, in response to the start command, Relay A is closed first,resulting in zero current/arcless switching (block 448).

As may be appreciated, the switching of the additional relays may causearcing. Accordingly, these relays may be switched via the POW andanti-arcing techniques described herein. A zero cross analysis isperformed (block 450), to pinpoint a time to switch the next of theremaining relays. Based upon the zero cross analysis, Relay B is closedusing the POW/anti-arcing techniques provided herein (block 452). Thisis illustrated in state 442C.

Next, Relay C is closed using the POW/anti-arcing techniques describedherein (block 454). This is illustrated in state 442D. By performing thesecond and third closings in this manner, arcing may be mitigated.

For subsequent iterations, the process 440 may remain the same, exceptthat the order of relay closings may change. For example, relay B may bethe first relay closed, followed by relay C and the relay A or followedby relay A and then relay C. In another subsequent iteration, relay Cmay be the first relay closed, followed by relay B and then relay A orfollowed by relay A and then relay B. By alternating ordering, contactdamage due to arcing may be mitigated, as each of the contacts share inthe burden of the closings that may cause a potential arc. Theseclosings, as discussed above, may result in contact erosion over time.By sharing the responsibility for these loads across multiple contacts,the overall life of the relay may be extended. Additionally, one relayin each sequence is closed under zero current/arcless switching whichmay also extend the life of the switching device.

FIG. 26 illustrates a process 470 for a first open operation todisconnect from a load. As illustrated, states of a three-pole circuitry472 are provided. In a first state 422A, all relays are closed, as arunning state is present (block 474).

Next, a stop command is provided (block 476). Because the open commandcan cause arcing, the POW/anti-arcing techniques described herein may beimplemented to break the initial relay connections. To do this, a zerocross analysis is performed (block 476). Based upon the zero crossanalysis, an initial relay is opened. As illustrated in state 472B, inresponse to the start command, Relay C is opened first, usingPOW/anti-arcing techniques (block 480).

As may be appreciated, the switching of an additional relay may continueto cause arcing. Accordingly, the next relay may also be switched viathe POW and anti-arcing techniques described herein. As illustrated instate 4723B, Relay B is opened using the POW/anti-arcing techniquesprovided herein (block 480). This is illustrated in state 442C.

Next, Relay A is opened under zero current/arcless switching (block484). This is illustrated in state 472D. By performing the openings inthis manner, arcing may be mitigated.

For subsequent iterations, the process 470 may remain the same, exceptthat the order of relay openings may change. For example, relay B may bethe first relay opened, followed by relay C and the relay A or followedby relay A and then relay C. In another subsequent iteration, relay Amay be the first relay opened, followed by relay B and then relay C orfollowed by relay C and then relay B. By alternating ordering, contactdamage due to arcing may be mitigated, as each of the contacts share inthe burden of the openings that may cause a potential arc. Theseopenings, as discussed above, may result in contact erosion over time.By sharing the responsibility for these loads across multiple contacts,the overall life of the relay may be extended. Additionally, one relayin each sequence is opened under zero current/arcless switching whichmay also extend the life of the switching device.

Minimizing Energy Available during a Fault Condition

In addition to the various schemes described above related tocoordinating the operations of relay devices 140 that provide power tomulti-phase system, the present embodiments may also involvecoordinating the operations of the contacts based on potential faultconditions (e.g., overcurrent, overvoltage) that may be present withinthe connected system. In one embodiment, the POW switching may beemployed to coordinate the opening and closing of contacts within therelay device 140 in response to detecting that a fault condition ispresent.

By way of example, the control system 198 may receive data from sensorsdisposed on each phase of a multi-phase system, from other controlsystems that are part of the industrial automation system, or any othersuitable data source that may provide data indicative of the presence ofany fault condition. Each phase may provide power to a multi-phase load,such as a motor, via a multi-phase relay device with independentlycontrollable contacts, via multiple single relay devices 140, or thelike. In one embodiment, the control system 198 may detect or determinethat a particular phase that may have a fault condition based on thereceived data. After detecting the particular phase that may have afault, the control system 198 may start opening the contacts of therelay device 140 phase associated with the next phase that may have avoltage or current waveform reaching its respective zero crossing first.In this way, the control system 198 may minimize the energy availablefrom the fault condition on the contacts of the respective relay device140. With this in mind, FIG. 27 illustrates a flow chart of a method 500for opening a contact associated with a particular phase based on thepresence of a fault.

Although the method 500 is described as being performed by the controlsystem 198, it should be noted that any suitable control circuit orsystem may perform the method 500. Referring now to FIG. 27, at block502, the control system 198 may receive an indication that a faultcondition is present on a part of a system connected to a respectiverelay device 140. The fault condition may be any type of fault such asan overload condition, an overvoltage condition, overcurrent condition,a temperature condition, or the like. The control system 198 may receivethe indication by way of data acquired from sensors, a signaltransmitted from another control system (e.g., controller, monitoringsystem), or any suitable signal generating device.

In some embodiments, the control system 198 may receive data thatrepresents a change in current (e.g., di/dt) for a respective phase maybe above some threshold. As such, the control system 198 may determinethat the current is rapidly rising to a potential fault condition (e.g.,overcurrent). In this way, the control system 198 may anticipate that afault condition is likely to occur and proceed to block 504.

At block 504, the control system 198 may identify a particular phasethat will have an electrical waveform that is approaching zero next.That is, in a multi-phase system, after receiving the indication that afault is present at block 502, the control system 198 may identify thenext phase in the multi-phase system that will conduct a voltagewaveform or current waveform that crosses zero. In some embodiments, thecontrol system 198 may monitor the voltage and current waveforms on eachphase of the multi-phase system using voltage sensors and currentsensors, respectively. In other embodiments, the control system 198 mayuse an internal clock to track the expected waveforms being conductedthrough each phase of the multi-phase system. To ensure that theexpected waveforms match the actual waveforms, the control system 198may calibrate the internal clock periodically with sensor data. By usingthe expected waveforms, the control system 198 may identify the nextphase crossing zero more efficiently without receiving data from othersensors.

After identifying the next phase crossing zero, the control system 198may, at block 506, send a signal (e.g., or remove a signal) to the relaydevice 140 associated with the next phase crossing zero. The signal maycause the contacts 262 and 264 to open. In some embodiments, the controlsystem 198 may coordinate the opening (e.g., energizing/deenergizingrelay coil 152) of the contacts 262 and 264, such that the contacts 262and 264 open at the zero crossing of the voltage or current waveform.

In certain situations, after detecting a fault in an industrial system,upstream or downstream circuit protection devices (e.g., breakers) mayopen after a number of cycles of an electrical waveform conducts througheach phase of the multi-phase system. To reduce the energy available forarcing or other undesirable condition, the control system 198 may openthe contacts associated with the next phase to cross zero. In this way,the devices connected upstream and downstream in the multi-phase systemmay be powered down while the energy available due to the faultcondition is minimized.

In addition to coordinating the operations of the relay device 140 basedon fault conditions, the present embodiments may include detecting shockor external events that may cause contacts to unintentionally changestates (e.g., closed to open). For example, certain external forces(e.g., magnetic, electric) may cause the contacts to open or close whenthey are expected remain closed or open, respectively. The externalforces may be vibrational or mechanical forces that may cause thecontacts to physically move. In this situation, the control system 198may detect the external event and adjust power provided to the relaydevice 140 to ensure that the contacts remain in a desired or expectedstate.

With this in mind, FIG. 28 illustrates a method 510 for controllingpower provided to the relay device 140 in response to detecting anexternal event. Like the method 500, the method 510 may be performed bythe control system 198 or any suitable controller or control device.

Referring now to FIG. 28, at block 512, the control system 198 mayreceive an indication of an external event from a sensor, anothercontrol system, or the like. As mentioned above, the external event maybe any event that may potentially cause the contacts 262 and 264 tochange states. The presence of the external event may also be inferredbased on related data. For instance, in some embodiments, anaccelerometer may be coupled to the contacts 262 or 264, to the housingof the relay device 140, or to another part of a component that may bephysically coupled to the contacts 262 or 264. The accelerometer maymeasure acceleration properties associated with a connected component.The acceleration properties, when above some threshold, may indicatethat the connected component is moving rapidly. Since the components ofrelay device 140 are expected to be stationary unless power to the relaycoil 152 is altered, the detection of movement within the relay device140 or on a component connected to the accelerometer may be indicativeof a potential external event (e.g., shock events).

At block 514, the control system 198 may determine the position of thecontacts 262 and 264 before the external event. That is, the controlsystem 198 may determine the expected state of the contacts 262 and 264during normal operation of the respective relay device 140. Based on thedetermined position and the occurrence of the external event, at block516, the control system 198 may adjust the power (e.g., current orvoltage) provided to the relay coil 152. In some embodiments, thecontrol system 198 may increase the coil current provided to the relaycoil 152 to ensure that the relay device 140 operates as desired and isnot influenced by external forces (e.g., magnetic, electric). That is,the additional current provided to the relay coil 152 may cause therelay coil 152 to produce a stronger magnetic field to ensure that thecontacts 262 and 264 are securely positioned in the same position as itwas prior to the external event.

In some embodiments, the amount of power adjustment provided to therelay coil 152 may be determined based on mechanical force dataassociated with the external event. For instance, the accelerometer mayprovide mechanical force data indicative of the force that is beingapplied to the contacts 262 and 264, and thus the power provided to therelay coil 152 should induce a magnetic force strong enough to overcomethe mechanical force created by the external event.

With the foregoing in mind, in some embodiments, the control system 198may determine a minimum amount of current that may be used to maintain adesired position or arrangement of the contacts within the relay device140. That is, the control system 198 may incrementally increase thecurrent used to drive the relay coil 153 until the armature 142 moves tocouple the contacts 262 and 264 together. After determining the minimumamount of current for driving the relay coil 152, the control system 198may provide the same amount of current each time the relay coil 152 isto be energized. In this way, the relay device 140 may use power (e.g.,current) more efficiently as compared to the rated current for the relaycoil 152. Although the minimum amount of current provided to the relaycoil 152 may be sufficient to maintain contact closure, an externalevent may cause the contacts 262 and 264 to inadvertently change states.As such, by employing the method 510 described above, the control system198 may increase the current provided to the relay coil 152 to ensurethat the contacts remain in the desired state.

In addition to conserving energy while driving relay coil 152, bydriving the relay coil 152 with the minimum current, the contacts mayalso change states more quickly when a fault or other condition ispresent that causes the relay device 140 to change states. As such, afault current present on one phase of a three-phase system may beisolated from the three-phase system more quickly, thereby reducing theimpact of the fault current on the three-phase load.

Although each of the preceding operations are described as a way tominimize the potential for arc energy to be present during an open orclose operation of the relay device 140, it may still be difficult toimplement one of the embodiments described herein to coordinate thetiming for opening the contacts relative to current flow or voltagepotential present on the contacts. In addition, other forces (i.e.,electromagnetic and gas pressure forces) generated due to a fault beingpresent may cause the contacts will open at an arbitrary instant intime. As such, arc energy may still be present when contacts of therelay device 140 change states. The armature may cause the contacts tocouple together again after they opened. In this case, the contacts mayweld together there because the arc energy creates a liquid metal (e.g.,silver) that may cause the contacts to stick together.

Keeping this in mind, to prevent this type of welding between thecontacts, an actuator may be employed to push contacts open from aparticular position. (e.g., position A or B). That is, an actuator maybe coupled to the armature 142 and controlled by the control system 198to change states of the contacts based on the presence of certainconditions. For example, FIG. 29 illustrates a method 520 forcontrolling an actuator in accordance with embodiments described herein.As discussed above, although the method 520 is described as beingperformed by the control system 198, any suitable controller or controlsystem may perform the method 520.

At block 522, the control system 198 may receive a change in current(e.g., di/dt) measurement from a sensor. The change in currentmeasurement may assist the control system 198 to anticipate when acurrent (e.g., through the contact or through another conductor) willexceed a threshold. At block 524, the control system 198 may determinewhether the change in current measurement exceeds some threshold. Thedetermination of the threshold may be based on a relationship betweenchange in current and a condition in which the contacts may changestates and may result in a weld between the contacts.

At block 526, the control system 198 may send a command to an actuatorto change or maintain the position of the contacts at the desired state.That is, if the contacts are positioned in an unexpected manner (e.g.,welded together), the actuator may be used to push the contacts apart tothe desired position. In addition, the actuator may be used to securethe contacts in the desired position, to prevent re-closure (e.g., aftercontact lift-off with arc) of the contacts with molten contact material.

It should be noted that the control system 198 may control the operationof the actuator based on the presence of a number of conditions (e.g.,detected fault, overcurrent detection). In some embodiments, theactuator may be activated or deactivated by actively switching off of aswitching element or an opening of the magnet system through openingforce data related to the movement of the contact.

In addition, the control system 198 may activate the actuator based ondetermining that the contacts are welded together. For example, theinductance of a closed and an open actuator is different. The inductanceof the actuator's magnet system in an open and closed position changesdue to an air gap in the magnet system. A constant current may beapplied to the magnet system and a change in voltage may be measured.Alternatively, a constant voltage may be applied to the magnet systemand a change in current may be measured. Based on the change in voltageor current, the control system 198 may determine the position of thecontacts and control the actuator accordingly. It should be noted thatthe contact status determination may be made via measurement of actuatorinductance during fault conditions and during the normal operation ofthe respective system.

Controlling Open and Close Operations of Contacts

Although the actuator, as described above, may be used to ensure thatthe position of contacts is correct or in an expected configuration, insome embodiments, the actuator may be used to position the armature 142to enable the contacts to open and/or close in an efficient (e.g., powerefficient) manner. That is, prior to the relay device 140 opening orclosing, the position of the armature 142 or the connected contacts maybe controlled in a manner to be placed at a particular angle or within adesired distance from another contact. By controlling the position ofthe armature 142, and thus the contacts connected thereto, the actuatormay ensure that the contacts (e.g., 262, 264) have a certain gapdistance between each other that may enable the armature to open orclose more efficiently.

Keeping this in mind, it should be noted that the speed in which acontact assembly opens influences the capacity in which the contacts canopen or break. In addition, the distance or gap between the two contactsin the moment the current flow (e.g., through the contacts) reaches itszero crossing should be at some threshold distance from each other toensure that the contacts do not restrike after opening. That is, if thedistance between the contacts after opening is larger than the thresholddistance, the amount of arc energy (e.g., ions, thermal time constant ofair column) that may be present between the contacts after the openoperation is completed may cause the temperature of the air gap betweenthe contacts to rise and create a suitable condition for restrike. Inother words, if the open operation causes the contacts to open to a gapthat is larger than some threshold, the air gap between the contacts mayreceive more heat (e.g., within the volumetric area) due to the arcenergy present from the voltage waveform.

In the same manner, after the contacts are opened, it may be beneficialto position the contacts such that the two contacts are greater than thefirst threshold distance and less than a second threshold distance. Byensuring that the gap distance between the two contacts are between thefirst and second threshold distances, the present embodiments place thecontacts in an optimal position to reduce the likelihood for restrike tooccur. As such, the open operation should be coordinated such that thecontacts open to a desired distance or optimal gap between each otherthat is greater than a first threshold distance (e.g., to preventrestrike) between the contacts and less than the second thresholddistance (e.g., to prevent contact bounce) between the contacts.

With this in mind, FIG. 30 illustrates a relay device 540 that issimilar to the relay device 140 of FIG. 6. However, the relay device 540includes an actuator 542 that may be coupled to the armature 142. Asshown in FIG. 30, a distance or gap between contacts 544 and 546 mayextend between range 548 and range 550 based on a position of an arm 552of the actuator 542. In some embodiments, the actuator 542 may be anysuitable a motor or other positioning device (e.g., stepper motor) thatmay be used to position the armature 142 by way of the arm 552. That is,the actuator 542 may extend or retract the arm 552, which may be coupledto the armature 142. As such, the armature 142 may be moved to positionthe contact 544 within a certain distance from the contact 546. In someembodiments, an armature may include the arm 552, which may be athreaded shaft or any other suitable component that may push and/or pullthe armature 142.

In some embodiments, the optimal gap may be determined for each contactassembly based on properties of the contact assembly. For example, thematerial of the contacts, the size or surface area of the contacts, theresistance of the spring 144, the inductance of the relay coil 152, theexpected voltage and current conditions for the contacts, and otherrelevant factors may be associated with determining the desired distancebetween contacts.

To control the position of the contacts with respect to the gaptherebetween, the control system 198 may send signals to the actuator542 to cause the actuator 542 to move the arm 552. The actuator 542 mayinclude any suitable deterministic positioning device in which theposition of the arm 552 may be moved in a controlled and known (e.g.,distance) manner. As mentioned above, the actuator 542 may include astepper motor that may have predefined increments in which the arm 552moves. As such, based on the incremental position of the stepper motor,the control system 198 may interpolate or determine the distance betweenthe contacts 544 and 546. In another embodiment, the inductance of therelay coil 152 or the actuator 542 may be used to determine or verifythe position of the armature 142 and thus the air gap between thecontacts 544 and 546.

Keeping the foregoing in mind, FIG. 31 illustrates a method 570 forcontrolling the open operation of the relay device 540. As discussedabove, although the method 570 is detailed as being performed by thecontrol system 198, the method 570 may be performed by any suitablecontroller or control system.

Referring now to FIG. 31, at block 572, the control system 198 mayreceive an indication that the relay device 540 is open. The indicationmay be received via a signal from the relay device 540, any suitablesensor, or some other control system. In some embodiments, the controlsystem 198 may infer that the relay device 540 is open based on otherfactors, such as voltage being absent from a device connected downstreamfrom the relay device 540 or the like. In addition, data obtained fromsensors disposed within the system may indicate that the relay device540 includes open contacts.

The indication received at block 572 may be representative of the relaydevice 540 opening or breaking the connection between the contacts 544and 546. The contacts 544 and 546 may open in response to a faultcondition being present or the like. As such, to prevent the contacts544 and 546 from re-striking, the control system 198 may ensure that thecontacts 544 and 546 are opened to a desired or optimal gap that reducesthe probability for restrike.

As such, at block 574, the control system 198 may determine a desireddistance or gap between the contacts 544 and 546. As discussed above,the desired gap may be determined for each contact assembly based onproperties of the contact assembly, such as the material of thecontacts, the size or surface area of the contacts, the resistance ofthe spring 144, the inductance of the relay coil 152, the expectedvoltage and current conditions for the contacts, and other relevantfactors may be associated with determining the desired distance betweencontacts. By way of example, the gap between contacts may be determinedbased on analyzing a likelihood of restrike occurring for certaincurrent values with respect to various gap distances. That is, for anumber of current values that may exceed a current rating for thecontacts, an analysis may be performed to determine a probability thatrestrike conditions (e.g., charge between contacts, ions in the air gap)for a number of distances for the gap. Based on the results of thisanalysis, the desired gap distance between the contact may bedetermined, such that the gap distance corresponds to the lowestprobability for restrike associated with the highest expected current(e.g., fault current) for the contacts.

In some embodiments, the analysis for determining the desired gapdistance between the contacts 544 and 546 may be determined prior toperforming the method 570. That is, the desired gap distance between thecontacts 544 and 546 may be determined during manufacturing or testingof the relay device 540. Alternatively, the desired gap distance may bedetermined dynamically based on the current conditions (e.g., current,voltage, fault current) present on the contacts 544 and 546. The currentconditions may be simulated based on machine learning algorithms thatdetermine an expected current and/or voltage present on the contacts 544and 546 based on sensor data obtained from downstream devices, upstreamdevices, or the like.

Referring back to the method 570, at block 576, the control system 198may send a command or signal to the actuator 542 to adjust the positionof the arm 552. The signal may cause the actuator 542 to move the arm552 to cause the armature 142 to move the position of the contact 544and achieve the desired gap between contacts 544 and 546. In someembodiments, the signal may include a number of steps for a steppermotor to move to achieve the desired distance. In addition, the distancebetween the contacts 544 and 546 may be verified based on the resistanceof the spring 144, the inductance of the relay coil 152, an indicationprovided by the actuator 542, or the like.

In addition to controlling the open operations, the actuator 542 maycontrol the gap between the contacts 544 and 546, such that they arepositioned in an optimal position to minimize contact bounce for a closeoperation. That is, when a close operation begins, the magnetic fieldprovided by the coil may cause the contact to close. By controlling theactuator 542 to position the contacts 544 and 546 closer to each other,as compared to a traditional relay device 140, the control system 198may reduce the bounce properties associated with the contacts 544 and546 by reducing the distance is traveled by the armature 142 to performthe close operation. Moreover, after the close operation is performed,the actuator 542 move back to a desired open position and wait for themagnetic field to collapse during an open operation to quickly have thearmature 142 positioned for the optimal open position as describedabove. As a result, the present embodiments described herein mayindependently be used to reduce torque transients and contact erosionexperienced by the contacts of the relay device.

With the foregoing in mind, FIG. 32 illustrates a method 590 forpositioning the gap between the contacts 544 and 546 in preparation fora close operation. As mentioned above, although the method 590 isdescribed as being performed by the control system 198, it should beunderstood that any suitable controller or control system may performthe method 590 described herein.

At block 592, the control system 198 may receive an indication that therelay device 540 has open contacts 544 and 546 using similar techniquesas described above with respect to block 572 of FIG, 44. In someembodiments, the indication may be received while the relay device 540is in an initialized state. That is, the relay device 540 may receive acoil current at the relay coil 152, such that the contacts 544 and 546(e.g., normally closed) open after the relay coil 152 is energized. Assuch, it should be noted that the embodiments described below withrespect to the method 590 may be performed on any suitable relay devicethat includes normally open contacts or normally closed contacts. In anycase, the indication that the contacts 544 and 546 are open may alsoinclude an indication that the contacts 544 and 546 are to remain openuntil a close operation is performed. As such, the method 590 may beperformed using a normally closed contact arrangement where the contacts544 and 546 open after the relay coil 152 is energized. However, itshould be understood that the method 490 may also be performed inconjunction with the method 570 described above to ensure that thecontacts 544 and 546 are positioned to balance between a gap thatprevents restrike and reduces the bounce properties between the contacts544 and 546 during a close operation.

In any case, at block 594, the control system 198 may determine adesired gap distance between the contacts 544 and 546 for performing aclosing operation. Like the block 574 of FIG. 31, the desired gapdistance may be determined based on testing that may occur duringmanufacturing or dynamically during the operation of the relay device540. That is, the gap between contacts may be determined based ondetermining a minimum distance for the contacts 544 and 546 to travel toreduce the likelihood of contact bounce occurring for certain currentvalues with respect to various gap distances. That is, for a number ofgap distances between the contacts, an analysis may be performed todetermine the bounce properties associated with a number of distancesfor the gap. Based on the results of this analysis, the desired gapdistance between the contacts may be determined, such that the gapdistance corresponds to the lowest number of expected bounces betweenthe contacts after a close operation is performed.

At block 596, the control system 198 may send a command to the actuator542 to cause the actuator 542 to move the arm 552 to achieve the desiredgap distance. As a result, the contacts 544 and 546 are positioned in anoptimal fashion to perform the close operation.

Automatically Configuring POW Settings

Although the embodiments described above detail various systems andmethods for increasing contact life or decreasing contact erosion, insome embodiments, POW switching may be configured to minimize a torqueripple that may occur when a three-phase power source is connected to aload (e.g., rotating load, motor, generator). That is, as discussedabove, the timing related to making or connecting a load to a powersource through relay devices that employ POW switching (e.g., closingoperation) is generally optimized to increase contact life. However, bycontrolling the points on waves in which each phase of a multi-phasepower supply connects to a rotating load, the control system 198 maycoordinate the closing of relay devices (e.g., closing of contacts) tosynchronize with the electrical waveforms present on the rotating loadto minimize a torque ripple that may occur when the rotating load firststarts rotating or when the rotating load is disconnected from the powersource and is reconnected to the power source.

In any case, depending on the operation of the connected equipment, itmay be beneficial to allow a user to select whether the relay devicesare to be optimized with regard to increase contact life or decreasetorque ripples. For example, a small motor may turn on and offfrequently, and, as such, a user may prefer that the contact life isoptimized to preserve the ability of the small motor to continue tooperate for a longer period of time. In another example, a 10-horsepowermotor may actuate a mechanism that is susceptible to stress andshortened life due to torque spikes that occur at startup. In thissituation, a user may wish to minimize start torque ripple.

With these scenarios in mind, in certain embodiments, the relay devicesdescribed herein may be configurable to operate in a manner that willpreserve or extend contact life or reduce the presence of torqueripples. That is, by controlling the point on the respective electricalwave (e.g., POW switching profiles) in which the respective relaydevices close to connect to a load, the control system 198 may adjustthe points on the respective electrical waveforms that the relay devicesconnect the loads to the power source. In some embodiments, the controlsystem 198 may receive an indication related to operating the relaydevices to preserve contact life or reducing torque ripples the using aswitch disposed on the relay device, a jumper on a printed circuit board(PCB) that hosts the relay device, or any other suitable physicalcomponent (e.g., hardware) that may be set by the user. In someembodiments, the relay device may include a physical dial that may bemoved to enable the user to select whether the relay should optimize forcontact life, torque ripple, or some balance between the two. That is,the dial may include a range of operation parameters that correspond topreserving a maximum life of the contact to about a 10% torque ripplereduction in starting current provided to the load.

In addition to a physical dial, the control system 198 may receive auser input via a visualization representative of a dial that may bedisplayed on an electronic display. As such, the user may specify to thecontrol system 198 a manner in which it may control the open and closeoperations of the relay device based on the preference of the user.

In some cases, the open and close operations of a relay device iscontrolled based on a POW switching profile used by the control system198 to control the respective relay devices. However, the POW switchingprofile used to control the respective relay device may changedynamically based on a history of use of the load equipment (e.g.,motor) being controlled by the relay device. That is, for example, thecontrol system 198 may monitor and record the operations of therespective load device over a period of time and dynamically adjust themanner in which the respective relay devices operate to maximize contactlife or minimize torque ripple based on the operation of the loaddevice. In this way, during certain periods of operation, the relaydevice may operate in a particular mode that may be beneficial to theoverall system performance. For instance, the control system 198 maydetermine an operating frequency of a load device, a frequency of startand stop operations performed during a period of time, load conditions(e.g., constant load, variable load, capacitive load) of the device, andother parameters to determine whether it may be more beneficial tomaximize contact life or minimize torque ripples for the overallperformance of the industrial system.

With the forgoing in mind, FIG. 33 illustrates a method 560 foradjusting the POW switching profile based on the load device connectedto the respective relay device. As mentioned above, although the method560 is described as being performed by the control system 198, it shouldbe understood that any suitable control system or controller may performthe method 560.

Referring now to FIG. 33, at block 562, the control system 198 maydetermine a type of load connected to the relay device. In someembodiments, the control system 198 may receive data from the respectiveload device. The data may be indicative of nameplate data thatcorresponds to the type of device, a rating for the device, and thelike. For instance, the nameplate data for a connected device may beprovided to the control system 198. The nameplate data may be used todetermine a set of operating parameters for the relay device based onthe specific device controlled by the relay device, based on the loadpresent on the relay device, and the like. In addition to the nameplatedata, metadata or data that is related to the specific device or loadmay be provided to the control system 198.

In some embodiments, the control system 198 may ping or send a signal tothe load device to determine the type of load that may be connected tothe device. That is, the control system 198 may send an electricalsignal to the load device via the respective relay device and determinethe type of the load device based on detected back EMF signals or thelike. In other embodiments, the control system 198 may receive data fromother control systems that may have access to information related to theload device connected to the relay device controlled by the controlsystem 198. Alternatively, the control system 198 may receive input datafrom a user that identifies the type of load device.

In some embodiments, the control system 198 may determine whether theload device corresponds to an inductive or capacitive load. That is, byevaluating a load type (e.g., inductive/capacitive) connected to therelay device, the control system 198 may determine how the relay deviceshould balance between the operating for optimizing between contact lifeand minimizing torque ripple. For instance, since the ideal angle forcapacitive loads and the ideal angle for inductive loads are oppositesof each other, the control system 198 may set a default setting for therelay device at a firing angle (e.g., 45°) that is between the idealcapacitive and ideal inductive loads. The control system 198 may thenmonitor whether the voltage waveform of the load device leads of lagsthe current waveform to determine whether the load device is capacitiveor inductive. In this way, the control system 198 may determine a POWswitching profile for the relay device that may protect load devicesfrom potential damage. For instance, if the control system 198 used aPOW switching profile that corresponds to an ideal angle for inductiveload for a load that was actually capacitive, the load device mayreceive a relatively high inrush current that could damage the loaddevice. By employing the technique described above, the control system198 may minimize the amount of damage that the load device mayexperience.

After determining the type of load device connected to the respectiverelay device, the control system 198 may, at block 564, determine a POWswitching profile to use for the respective relay device. That is,depending on the normal operating parameters of the load device, theexpected frequency in which the load device operates, the number oftimes that the load device is cycled on and off, the amount of powerused by the load device, another other suitable factors, the controlsystem 198 may configure the POW settings for open and close operationsof its relay device to preserve contact life or minimize torque ripples.

In some embodiments, the control system 198 may access a lookup table orother data that may provide an indication as to what POW switchingprofile to use for the respective load type. In addition, the controlsystem 198 may determine the POW switching profile to use based onhistorical analysis of various types of loads connected to the relaydevice. That is, the control system 198 may track the various types ofload devices connected to the respective relay devices over a period oftime.

After determining the POW switching profile to use, the control system198 may begin controlling the open and close operations according to theidentified POW switching profile. That is, if the control system 198determines that the load device switches on and off more than athreshold amount of times within some amount of time, the control system198 may use a POW switching profile that preserves contact life byperforming opening and closing operations at the zero crossing or usingany of the other techniques described herein. Alternatively, if thecontrol system 198 determines that the load device is susceptible todamage due to torque ripples, the control system 198 may select the POWswitching profile that reduces the likelihood of torque ripples beingpresent but may not allow the relay device to perform open and closeoperations at the zero crossing of various electrical signals.

After the relay device operates according to the determined POWswitching profile, the control system 198 may, at block 566, monitor theuse of the load device and/or the opening and closing operations of therelay device for a period of time. As such, the control system 198 maymonitor whether the POW switching profile selected for the load devicesuits the performance of the load device or the relay device. In thisway, at block 568, the control system 198 may adjust the POW switchingprofile based on the monitored use of the respective device.

In some embodiments, the method 560 may be performed continuously todynamically adjust the POW switching profile used to control the relaydevice throughout the life of the relay device. As such, if theperformance or use of the load device changes, the control system 198may automatically adjust the POW switching profile without userinteraction to ensure that the relay device and/or load device isprotected. Moreover, by using the method 560, the control system 198 mayautomatically assess how to control the relay device without receivinguser input or guidance, thereby protecting the various devices fromhuman error or from the lack of knowledgeable human operators beingpresent to initialize the operation of the load device or the relaydevice.

In addition to determining POW switching profile based on the load typeand the monitored data, the control system 198 may coordinate theselected POW switching profile with other protection circuitry that maybe in the system. That is, a protection component (e.g., circuitbreaker) connected to the relay device may provide information (e.g.,current detected through current transformer of circuit breaker) relatedto the operation of the relay device, the connected load device, or thelike. For example, if the relay device uses a POW switching profile thatoptimizes contact life, the current ripple and inrush current for therespective device being controlled by the relay device may increase.This increased current amount may cause the protection component toinadvertently trip or actuate (e.g., during startup in rush current),thereby providing data related to the trip window or sensitivity of theprotection component.

Keeping this in mind, FIG. 34 illustrates a flow chart of a method 570for adjusting the POW switching profile for a relay device based onconnected protection equipment data. As shown in FIG. 34, at block 572,the control system 198 may receive data related to protection equipment.The data may be received from protection equipment (e.g., circuitbreakers, switchgear), from other control systems, or the like.

The data may be indicative of times and conditions in which theprotection equipment activated. That is, the data may include electricalproperties (e.g., voltage, current) that correspond to causing theprotection equipment to trip. In some embodiments, the data may includeinformation indicating that the protection equipment should not havetripped. The information may be received as input to the control system198 to designate certain trips by the protection equipment as true orfalse trips.

In addition, the data may include sensitivity data regarding theprotection equipment. The sensitivity data may include a range ofvoltage levels that the protection equipment received within a periodtime that may have caused the protection equipment to inadvertentlytrip. In some embodiments, the data may be received from a databasecontaining manufacturing datasheets regarding the protection equipment.The data may detail the current ripples or voltage spikes that may causethe protection equipment to falsely trip.

After receiving the data related to the protection equipment, at block574, the control system 198 may adjust a POW switching profile for therelay device based on the data. The control system 198 may adjust thePOW switching profile for the relay device to prevent the inadvertenttripping of the protection component. As such, the control system 198may reduce the likelihood of nuisance tripping by the protectionequipment.

In some embodiments, the control system 198 may employ an angleauto-tuning process that identifies the limits of connected protectioncomponents and adjusts the POW switching to avoid reaching these limits.That is, during an initialization phase, the control system 198 maycontinuously adjust the POW switching profile for the relay device toidentify the situations that cause the connected protection equipment toinadvertently trip. The control system 198 may adjust the firing anglein which the contacts of the relay device change states to detectwhether the protection equipment may inadvertently trip due to currentrippled, voltage spikes, or the like. Based on the conditions in whichthe protection equipment inadvertently trips, the control system 198 maydetermine the POW switching profile to use to control the switching ofthe contacts within the relay device.

In addition, the control system 198 may automatically tune the operationof the relay device based on a machine learning algorithm and dataavailable to the control system. For example, the control system 198 maymonitor the operation of the relay device for an initial period (e.g.,100 hours) and determine a best operation mode for the relay deviceduring the various operation cycles of the load device. In anotherembodiment, load or device data that may be specific to the device beingcontrolled by the relay device may be provided to the control system 198associated with operating the relay device to determine a POW switchingprofile that suits longevity of the relay device.

Along with tuning the operation of an individual device, the controlsystem 198 may coordinate the sequencing or the operation of a number ofload devices using different POW switching profiles for multiple relaydevices that operate multiple load devices. That is, in certaincoordinated or parallel system, it may be useful to power on loaddevices according to a particular sequence to ramp up the inrush currentor to reduce the peak inrush current being provided to downstreamdevices.

With this in mind, FIG. 35 illustrates a flow chart of a method 580 forcoordinating the activation of multiple load devices using various POWswitching profiles. In some embodiments, the control system may, atblock 582, receive data related to the operations of various loaddevices and certain load conditions for the load devices. The data maybe received from the load devices, sensors disposed downstream from therelay device, other control systems or the like.

At block 584, the control system 198 may determine the POW switchingprofiles for the multiple relay devices used to provide power to themultiple load devices. The control system 198 may account for the loadconditions present on the load devices when determining the appropriatePOW switching profile to use for the respective relay device. That is,the control system 198 may delay switching or closing certain relaydevices by adjusting the respective POW switching profiles toaccommodate for the various monitored parameters. For example, if one ofthe load devices causes an inrush current greater than a threshold to begenerated when powered on, the control system 198 may delay turning onor connecting power to another load device that may be in a parallelsystem (e.g., electrically parallel) to avoid the inrush current frombeing provided to other devices. Alternatively, the control system 198may detect or anticipate the inrush current and adjust the POW switchingprofile for other relay devices to close at zero current crossing toavoid potential arcing events. In addition, the control system 198 maycoordinate the turning on of various devices via respective relaydevices to ensure that no two devices are powered on at the same time toensure that the inrush current or other electrical specifications aremaintained.

At block 586, the control system 198 may coordinate the activationand/or deactivation of the load devices using the POW switching profilesdetermined at block 584. As such, the control system 198 may controlopen and close operations of the armature in the relay device based onthe updated POW switching profile. In addition, the control system 198may coordinate the open and closing operations of various relay devicessuch that load devices are activated and/or deactivated in a controlledfashion to ensure that each load device operates within expectedelectrical parameters for the respective load device. That is, thecontrol system 198 may coordinate the activation and/or deactivation ofeach load device to ensure that current ripples, voltage spikes, inrushcurrent, and other electrical parameters do not cause damage to any ofthe load devices connected in parallel or in series with each other.

It should be noted that the process for sequentially turning-on multiplerelays to reduce torque/current ripple will assist in reducing overallsystem torque ripple, just as adjusting and optimizing an alpha anglethat the relay devices are closed or opened. In addition, this processmay be used in conjunction with an alpha angle optimization process thatmay involve a staged/staggered turn-on of multiple motors.

Controlling Firing Delay in Multi-Phase Relay Devices

A multi-phase relay device may include multiple armatures that controlpositions of respective sets of contacts. With this in mind, an alphaangle of three phase POW controlled relay device corresponds to a timeat which two phases of the three phases are energized. The alpha angleis followed by a beta event when the third phase is energized. In someembodiments, the beta delay may be controlled to cancel or reduceharmonics that may be present on the overall system. By employing theembodiments described herein, the control system 198 may adjust the POWswitching profiles for multi-phase relay devices to reduce harmonics,provide a soft start option for the load, and the like.

With this in mind, FIG. 36 illustrates a flow chart of a method 590 foradjusting the beta delay to energize a load device. As discussedthroughout this disclosure, although the method 690 is described asbeing performed by the control system 198, any suitable control systemor controller may perform the methods described herein. Referring now toFIG. 36, at block 592, the control system 198 may receive current datarelated to current being received by a load device (e.g., motor). Thecurrent data may be received via a current sensor or other suitablesensor capable of measuring current waveforms received at the loaddevice. The current data may provide information related to theresonance frequency of the load device.

At block 594, the control system 198 may use the resonance frequencydata to determine whether harmonics are present on the load or expectedto be present on the load. At block 596, the control system 198 may usethe expected harmonics that may be present when starting the load deviceto adjust the beta delay associated with energizing a particular phaseof the input power to reduce or minimize the presence of the harmonicson the load.

In some embodiments, the control system 198 may cycle power to the loaddevice and receive the current data from sensors to detect whetherharmonics are present on the load side. In addition, the control system198 may incrementally adjust the beta delay after each cycle to identifythe beta delay that enables the load device to operate with the lowestamount of harmonics.

In some devices, a three-phase power source connected to a load via athree-phase relay device to magnetize a core of a motor. Keeping this inmind, FIG. 37 illustrates a flow chart of a method 600 for adjusting thebeta delay based on whether the load includes a magnetic core. At block602, the control system 198 may receive an indication that a magneticcore is present in the load device. In one embodiment, the controlsystem 198 may receive a user input indicative of the load including themagnetic core. In another embodiment, a control system that operates theload device may send an indication that the load device includes amagnetic core to the control system 198. In yet another embodiment, thecontrol system 198 may receive nameplate data from a database or othersuitable storage that provides information regarding the load device.

At block 604, the control system 198 may adjust the beta delay based onthe presence or lack of presence of the magnetic core in the loaddevice. The beta delay may be used to provide additional time for thecore to magnetize before proceeding with the operation of the motor. Insome embodiments, the beta delay may vary directly to the size of themagnetic core. That is, as for magnetic cores that are larger thanothers, the control system 198 may extend the beta delays further, ascompared to the load devices with smaller magnetic cores.

In some embodiments, the control system 198 may cycle power to the loaddevice and receive the data from sensors to detect whether a magneticcore is present on the load device. In addition, the control system 198may incrementally adjust the beta delay after each cycle to identify thebeta delay that enables the load device to have a sufficient amount oftime to energize its magnetic core.

In yet another embodiment, the control system 198 may use a number ofPOW open and close operations (e.g., on and off signals) with variousbeta delays to provide a soft starter feature for a respective load. Forexample, the control system 198 may use a POW close operation to providepower to a load device. The POW close operation may be provided incycles along with open operations to provide a pulse width modulated(PWM) signal to the downstream devices. The first POW close operationmay be provided with a first beta delay at, for example, a half-cycledelay, while the second POW close operation may be provided with a betadelay at a full cycle.

With the foregoing in mind, FIG. 38 illustrates a flow chart of a methodfor coordinating the POW switching profile of relay devices for softstart operations. At block 612, the control system 198 may receive arequest to implement a soft start. The request may be received via userinput to the control system 198. After receiving the request, thecontrol system 198 may, at block 614, coordinate the POW switchingprofiles of the relay device to perform a soft start operation asdescribed above.

The controlled cycling on and off of the respective device may also becoordinated by the control system 198, such that different relays areused to control each respective phase. That is, each phase may be cycledon and off at different intervals or according to a different sequenceusing POW switching profiles. In this way, different phases are beingused to energize the respective device instead of using the beta delayto continuously connect one particular phase of power to the respectivedevice. For instance, the phases that are connected to the respectivedevice may be coordinated using the POW switching according to a roundrobin sequence, such that phases A and C are connected to the respectivedevice with the alpha angle, phases A and B are connected to therespective device with the alpha angle during a subsequent cycle, and soforth. In this way, instead of repeatedly using one particular phase toenergize the connected device, the contact of the respective relay maybe preserved to operate for longer life cycles.

POW Switching to Synchronize with Rotating Load

In addition to controlling the beta delay for various situations, thecontrol system 198 may use different POW switching profiles toresynchronize a power source (e.g., a starter) with a rotating load(e.g., motor). That is, the control system 198 may monitor the powerproperties of the rotating load to understand the frequency propertiesof the power provided to the rotating load and remake the powerconnection to the rotating load (e.g., high inertia load) at anoptimized point on wave. For instance, a rotating load may continue torotate while power has been removed from the power source. If power isto be reconnected, the control system 198 may optimize thesynchronization of providing power back to the rotating load withoutintroducing any additional torque than necessary to maintain the desiredfrequency.

With this in mind, FIG. 39 illustrates a flow chart of a method 620 forresynchronizing a power connection to a rotating load. As such, themethod 620 may be performed after receiving an indication that therotating load is no longer connected to a power source or that at leastone phase of the rotating load is no longer connected to the rotatingload. After at least one phase of power is removed from the rotatingload, the rotating load device may reduce the speed in which it rotates.As such, the electrical waveforms conducting on the windings andinternal circuitry of the rotating load device may also be changing inlight of the reduced speed.

To reconnect the power to the rotating load device, the control system198 may connect power to the rotating load device using a particularpoint-on-wave (POW) switching profile that ensures that the rotatingload device resumes its rotation while minimizing the introduction ofadditional torque to maintain a desired frequency. As shown in FIG. 39,at block 622, the control system 198 may receive power propertiesassociated with a rotating load. The power properties may include anelectrical frequency of the voltage signal and/or current signal beingprovided to each phase of a rotating load. The power properties may bereceived via voltage sensors, current sensors, or the like.

In some embodiments, the power properties may be determined by thecontrol system 198 based on a speed in which a shaft of the rotatingload device rotates and data indicative of power properties provided toeach phase of the rotating load device. Using the speed of the shaft andthe data indicative of power properties provided to each phase of therotating load device, the control system 198 may determine a frequency(e.g., voltage waveform frequency) that the rotating load device isrotating. In addition, the control system 198 may determine a rate ofdeceleration of the rotating load device, such that the control system198 may anticipate the frequency of the rotating load device at acertain time.

At block 624, the control system 198 may determine frequency propertiesof the power present on the rotating load device based on the datareceived at block 622. The frequency properties may include an amplitudeof voltage and current provided to each phase of rotating load device, aperiod or frequency of the voltage or current waveform provided to eachphase of the rotating load, and the like.

At block 626, the control system 198 may reconnect the power to therotating load device based on the frequency properties of the powerpresent on the rotating load device. In some embodiments, the controlsystem 198 may determine the expected frequency properties present onthe rotating load device at a particular time in the future and performa close operation for a particular phase of power connected to therotating load device using a POW switching profile that matches afrequency and amplitude of the detected frequency properties. In someembodiments, the control system 198 may control the open and closingoperations of the relay device to provide the power at the desiredfrequency properties.

By connecting the power to the rotating load device in this fashion, thecontrol system 198 may synchronize the power provided to the rotatingload device, such that the rotating load device is optimized to resolvea residual voltage difference between the power source and the rotatingload device to zero after the POW switching remakes the connectionbetween the power source and rotating load. To optimize thesynchronization, as mentioned above, the control system 198 may use thedetermined the amplitude of the voltage waveform and the frequency ofthe voltage waveform to coordinate the POW switching for one or moresets of contacts to perform close operations that will be coordinated toconnect the power source to the load at the determined amplitude andtime.

In some embodiments, the back EMF signal may be used to determine theelectrical properties of the rotating load. In this case, the back EMFsignal may be determined by the control system 198 or received via asensor. The back EMF signal may be used to determine the frequencyproperties of the power present on the rotating device. However, if theback EMF signal collapses, the control system 198 may connect one phaseof a three-phase power source (e.g., pulsing a single-phase power) tothe rotating load to determine the power characteristics of the rotatingload and remake the connection between the power source and the rotatingload at a time or point on a voltage waveform that may reduce harmonics,minimize additional torque being provided on the rotating load device,or the like. In some embodiments, if the control system determines thatthe rotating load is rotating in an opposite or reverse direction, thecontrol system may adjust its optimization process accordingly.

With this in mind, FIG. 40 illustrates a flow chart of a method 630 forreconnecting power to a rotating load device after detecting that theback EMF signal has collapsed. Referring to FIG. 40, at block 632, thecontrol system 198 may receive an indication that the back EMF signalfrom a rotating load device has collapsed or decreased to zero. In someembodiments, the control system 198 may monitor the back EMF signal thatcorresponds to feedback from the rotating load device via a sensor orother suitable measurement circuitry.

The indication that the back EMF signal has collapsed may alert thecontrol system 198 that the rotating load device may be offline. Assuch, the control system 198 may attempt to remake a power connection tothe rotating load device when the upstream power becomes available. Atblock 634, the control system 198 may send one or more voltage orcurrent pulses to a single phase of the rotating load device via arespective contact of a respective relay device. The electrical pulsesmay be used to provide energy to the rotating load device, such that therotating load device may begin or resume rotating.

At block 636, the control system 198 may determine power propertiesassociated with the rotating load based on the back EMF signal receivedafter the electrical pulses are sent to the rotating load device atblock 634. The power properties determined based on the subsequent backEMF signal may represent the voltage or current waveform that ispresently on the rotating load device. In this way, at block 638, thecontrol system 198 may reconnect power to the rotating load device via arespective set of contacts based on the power properties determined atblock 634. That is, the control system 198 may reconnect power to therotating load device using a POW switching profile that may bedetermined using the procedure described above in block 626, using adelayed beta angle, or any suitable methodology that may enable therotating load device to resume its rotation at a rate or desiredfrequency.

Printed Circuit Board (PCB) Implementations

Multiple motors associated with a machine or a process may be controlledusing a control system and motor starters. However, routing wiresbetween each motor controller and various motors may pose variousmanufacturing and assembly challenges. For example, each wire to berouted between each motor starter and a respective motor is typicallylabeled to ensure that the wire is connected to an appropriate terminalto effectively control the respective motor. However, this process istime and work intensive. Accordingly, certain embodiments of the presentapplication relate to implementing multiple motor controllers (e.g.,motor starters) on a printed circuit board (PCB) to automaticallyoperate and control a respective number of motors coupled to the PCB.For example, after a number of motor starters are integrated withcertain terminals of the PCB, control circuitry of the PCB mayautomatically adjust circuit connections on the PCB to properly routewires used to control each motor to the appropriate motor starter. Thatis, in one embodiment, the control circuitry may send a signal to eachload-side terminal of the PCB in a controlled fashion to measure theback electromotive force (EMF) properties of each motor to determine howthe respective wires connected to each load-side terminal are connectedto each respective motor starter. Based on the back EMF properties ofeach motor, the control circuitry may adjust the circuit connections onthe PCB to properly route the wires between each motor to theappropriate motor starter. As such, embodiments of the presentapplication provide an initialization process of motor starters coupledto the PCB that automatically configures the motor starters to operateand control respective motors coupled to the PCB, thereby reducing thetime to assemble and manufacture motor control systems and minimizes theprobability of incorrectly wiring such motor control systems.

After performing the initialization process described above, the controlcircuitry of the PCB may also monitor and control the operation of oneor more relays of each motor controller coupled to the PCB. For example,the control circuitry may detect the number of relays present on the PCBand determine the number of motors the PCB is capable of controlling. Asdescribed above, the control circuitry of the PCB may perform theinitialization process of the motor starters coupled to the PCB tomeasure the back EMF properties of each motor connected to the PCB andadjust the circuit connections on the PCB to properly route the wiresthat control each motor to the appropriate motor starter. The PCB maythen determine the number of motors currently coupled to the PCB anddisable any relays that are not electrically connected to such motorsthrough the PCB. In this way, the control circuitry may increase thepower efficiency of the motor control system by disabling any relaysthat are not currently utilized.

In yet another embodiment, the control circuitry of the PCB mayautomatically configure a collection of relays on the PCB to operateaccording to different current ratings of the types of motors coupled tothe PCB and/or the number of motors coupled to the PCB. For example, thecontrol circuitry of the PCB may configure one or more relays of the PCBto support two lower amp-rated motors or one higher amp-rated motor viathe initialization process described above. By measuring the back EMFproperties of each motor coupled to the PCB and adjusting the circuitconnections on the PCB to electrically couple the relays with the motorscoupled to the PCB based on the back EMF properties, the controlcircuitry of the PCB may automatically configure the relays to supportdifferent types of motors and/or different numbers of motors.Additionally, the control circuitry may provide a recommendation to addone or more jumpers to the PCB to make appropriately rated relayconnections based on the number of motors and/or the type of motorscoupled to the PCB. Accordingly, the control circuitry may increase theflexibility of a single PCB to be utilized in various applicationsassociated with motor control systems, thereby reducing the number ofPCBs needed to implement such applications.

With the foregoing in mind, FIG. 41 illustrates an exemplary PCBimplementing a motor controller 700 (e.g., a motor starter). The motorcontroller 700 is electrically coupled to a PCB 702 that supportsvarious components of the motor controller 700 and facilitates routingof power signals, data signals, and control signals during operation. Incertain embodiments, the motor controller 700 may be packaged in amanner that conforms to industry standards for three-phase automationdevices, 208, 230, or 560 VAC motor controllers, or other motor starterapplications. In the illustrated embodiment, the PCB 702 and the mountedcomponents to the PCB 702 are supported on a base 704 and are covered bya housing or an enclosure 706 that couples to the base 704.

As illustrated in FIG. 41, three relays 708, 710, 712 of the motorcontroller 700 are mounted to the PCB 702 and are electrically coupledto other circuit components through the PCB 702. The relays 708, 710,712 may be mounted to the PCB 702, for example, through pins or tabs 724extending from the packaging of the relays 708, 710, 712. Each pin ortab 724 may be electrically coupled to a respective hole 726 in the PCB702 (e.g., by soldering). The relays 708, 710, 712 have controlconnections that facilitate the automatic opening and closing of therelays 708, 710, 712 (i.e., automatically changing the respectiveconductive state of each relay) by applying control signals through thecontrol connections to the relays 708, 710, 712. Additionally, the motorcontroller 700 is coupled to a three-phase power source 716 vialine-side terminals 714. The relays 708, 710, 712 may receivethree-phase power from the line-side terminals 714 through the PCB 702and output the three-phase power through respective load-side terminals722 to a motor 728. It should be noted that the three-phaseimplementation described herein is not intended to be limiting. Morespecifically, certain aspects of the disclosed techniques may beemployed on single-phase circuitry.

A power supply 718 is also coupled to the PCB 702. The power supply 718may provide power to control circuitry 720 through the PCB 702. Morespecifically, the power supply 718 receives power from one or more ofthe phases of power from the line-side terminals 714 and converts thepower to regulated power (e.g., direct current (DC) power). The controlcircuitry 720 receives the regulated power from the power supply 718 andutilizes the regulated power for monitoring, computing, and controlfunctions, as described herein.

In certain embodiments, to facilitate operation of a machine or aprocess, the motor 728 may include an electric motor that convertselectric power to provide mechanical power. To help illustrate, theelectric motor may provide mechanical power to various devices, asdescribed herein. For example, the electric motor may provide mechanicalpower to a fan, a conveyer belt, a pump, a chiller system, and variousother types of loads that may benefit from the advances proposed.Additionally, the machine or the process may include various actuators(e.g., motors 728) and sensors. The motor controller 700 may control amotor 728 of the machine or the process. For example, the motorcontroller 700 may control the velocity (e.g., linear and/orrotational), torque, and/or position of the motor 728. Accordingly, asused herein, the motor controller 700 may include a motor starter (e.g.,a wye-delta starter), a soft starter, a motor drive (e.g., a frequencyconverter), or any other desired motor powering device.

FIG. 42 illustrates a schematic representation 730 of the motorcontroller 700. As illustrated in FIG. 42, the relays 708, 710, 712 areelectrically coupled to the control circuitry 720 and the power supply718 via the control circuitry 720. The relays 708, 710, and 712 mayoperate according to any of the techniques described above. Conductivetraces 732 in or on the PCB 702 and between the line-side terminals 714and the relays 708, 710, 712 may facilitate provision of the three-phasepower from the power supply 718 to the relays 708, 710, 712. Similarly,conductive traces 734 in or on the PCB between the load-side terminals722 and the relays 708, 710, 712 may facilitate provision of thethree-phase power from the relays 708, 710, 712 to the motor 728 via theload-side terminals 722. In some embodiments, the conductive traces 732,734 may be made by conventional PCB manufacturing techniques (e.g.,plating, etching, layering, drilling, etc.).

Each relay 708, 710, 712 may be an electromechanical device thatcompletes a single current carrying path (or interrupts the currentcarrying path) under the control of an electromagnetic coil structure asdiscussed above. As illustrated in FIG. 42, the relays 708, 710, 712include a contact section 736 and a direct current (DC) operator 738.The contact section 736 typically has at least one moveable contact andat least one stationary contact. The moveable contact is displaced underthe influence of a magnetic field created by energization of a coil ofthe DC operator 738 via control signals provided by the controlcircuitry 720. Each relay 708, 710, 712 also has a current sensor 740that allows for detection of currents of incoming and/or outgoing power.In some embodiments, the current sensor 740 may be a separate componentthat is associated with the conductive traces 732, 734 that facilitateprovision of the three-phase power from the line-side terminals 714 tothe relays 708, 710, 712 or facilitate provision of the three-phasepower from the relays 708, 710, 712 to the load-side terminals 722.

Additionally, conductive traces 742 in or on the PCB 702 electricallycouple the DC operator 738 of each relay 708, 710, 712 to the controlcircuitry 720. Further, conductive traces 744 in or on the PCB mayfacilitate provision of the three-phase power between the power supply718 and the control circuitry 720. In some embodiments, additionalmonitoring, programming, data communication, feedback, and the like, maybe performed by the components of the motor controller 700. In suchembodiments, the signals may be provided and exchanged by additionalconductive traces in or on the PCB 702.

FIG. 43 illustrates a block diagram 746 of various components of thecontrol circuitry 720. As illustrated in FIG. 43, the control circuitry720 has one or more processors 748 and memory circuitry 750. Morespecifically, the memory circuitry 750 may include a tangible,non-transitory, computer-readable medium that stores instructions, whichwhen executed by the one or more processors 748 perform variousprocesses described herein. It should be noted that “non-transitory”merely indicates that the media is tangible and not a signal. Althoughdescribed as being part of the PCB 702, the control circuitry 720 may beseparate from the PCB 702 and communicate with components on the PCB702. It should also be noted that the control circuitry may also includeelements described above as part of the control system 198.

In some embodiments, operation of the motor controller 700 (e.g.,opening or closing of the relays 708, 710, 712) may be controlled by thecontrol circuitry 720. The control circuitry 720 may also have one ormore interfaces 752 to exchange signals between the control circuitry720 and sensors, external components and circuits, relay coils, and thelike. The control circuitry 720 also has conductors 754, 756, 758 orpinouts for communicating with various devices via conductive traces ofthe PCB 702. For example, conductors 754 may receive sensor data fromvarious sensors 770 associated with the power supply 718, the motorcontroller 700, the motor 728, and the like. More specifically, thesensors 770 may monitor (e.g., measure) characteristics (e.g., voltageor current) of the power. Accordingly, the sensors 770 may includevoltage sensors and current sensors. The sensors 770 may alternativelybe modeled or calculated values determined based on other measurements(e.g., virtual sensors). Many other sensors and input devices may beused depending upon the parameters available and the application.Additionally, conductors 756 may exchange data with a programming orcommunications interface 772, and conductors 758 may provide controlsignals to the relays 708, 710, 712.

Although the PCB 702 described in FIGS. 60 and 61 is implemented with asingle motor controller 700, other PCB configurations may be implementedwith multiple motor controllers in order to control respective motors.In some embodiments, for example, a PCB may be implemented with morethan five motor controllers, more than ten motor controllers, or anyother suitable amount of motor controllers to control respective motorsof a particular machine or process. With the foregoing in mind, FIG. 44illustrates a block diagram 774 of an exemplary PCB 776 implemented witha number of motor controllers (e.g., MC_(N)) configured to control arespective number of motors (e.g., M_(N)) of a particular machine orprocess. Each motor controller (e.g., MC₁, MC₂, MC₃, MC₄, . . . MC_(N))may have three relays mounted to the PCB 776 associated therewith. Forexample, motor controller MC₁ may be associated with relays 778, 780,782, motor controller MC₂ may be associated with relays 784, 786, 788,motor controller MC₃ may be associated with relays 790, 792, 794, motorcontroller MC₄ may be associated with relays 796, 798, 800, and motorcontroller MC_(N) may be associated with relays 802, 804, 806. Therelays 802, 804, 806 associated with each motor controller MC_(N) areelectrically coupled to other circuit components through the PCB 776. Inparticular, the relays 802, 804, 806 have control connections thatfacilitate the automatic opening and closing of the relays 802, 804, 806(i.e., automatically changing the respective conductive state of eachrelay) by applying control signals through the control connections tothe relays 802, 804, 806. Each motor controller MC_(N) is coupled to athree-phase power source 808 via a set of line-side terminals 810. Therelays 802, 804, 806 of each motor controller MC_(N) receive three-phasepower from the set of line-side terminals 810 through the PCB 776 andoutput the three-phase power through respective load-side terminals 812to a respective motor M₁, M₂, M₃, M₄, . . . , M_(N). As described above,it should be noted that the three-phase implementation described hereinis not intended to be limiting. More specifically, certain aspects ofthe disclosed techniques may be employed on single-phase circuitry.

Additionally, a power supply 814 is coupled to the PCB 776. The powersupply 814 provides power to control circuitry 816 through the PCB 776.More specifically, the power supply 814 receives power from one or moreof the phases of power from the set of line-side terminals 810 andconverts the power to regulated power (e.g., direct current (DC) power).The control circuitry 816 receives the regulated power from the powersupply 814 and utilizes the regulated power for monitoring, computing,and control functions, as described herein. It should be noted that thepower supply 814 and the control circuitry 816 may have similarrespective features and functions as the power supply 718 and thecontrol circuitry 720 described herein.

As mentioned above, after a number of motor controllers MC_(N) (e.g.,motor starters) have been electrically coupled to the PCB 776, thecontrol circuitry 816 of the PCB 776 may perform an initializationprocess to automatically adjust circuit connections on the PCB toproperly route wires used to control each motor M_(N) to the appropriatemotor controller MC_(N). With this in mind, FIG. 64 illustrates a flowchart of a method 818 for the initialization process performed by thecontrol circuitry 816. In block 820, the control circuitry 816 may senda signal to each load-side terminal 812 of the PCB 776 in a controlledfashion to measure the back EMF properties of each motor M_(N)electrically coupled to the PCB 776 to determine how the respectivewires connected to each load-side terminal 812 are connected to eachmotor controller MC_(N). In some embodiments, the control circuitry 816may receive back EMF data (e.g., voltage data) associated with eachmotor M_(N) electrically coupled to the PCB 776 and determine the backEMF of each motor M_(N) based on the received data. In block 822, basedon the back EMF properties of each motor M_(N), the control circuity 816may determine the identity of each motor controller MC_(N) thatcorrectly corresponds to a particular motor M_(N).

In block 824, the control circuitry 816 may then adjust the circuitconnections on the PCB 776 to properly route the wires that control eachmotor M_(N) to the appropriate motor controller MC_(N). For example, thecontrol circuitry 816 may determine that the motor controller MC₁corresponds to the motor M₄ and the motor controller MC₄ corresponds tothe motor M₃. That is, the motor M₄ may be electrically coupled to thePCB 776 through load-side terminals 812 not ordinarily used to couple amotor corresponding to the motor controller MC₁ (e.g., not directly inline with or underneath the relays 778, 780, 782 of motor controller MC₁on the PCB 776), and the motor M₃ may be electrically coupled to the PCB776 through load-side terminals 812 not ordinarily used to couple amotor corresponding to the motor controller MC₄ (e.g., not directly inline with or underneath the relays 796, 798, 800 of the motor controllerMC₄ on the PCB 776). The control circuitry 816 may then automaticallyadjust the circuit connections on the PCB 776 to route the wiring thatcontrols the motor M₄ to the motor controller MC₁ and the wiring thatcontrols motor M₃ to the motor controller MC₄. That is, the PCB 776 mayinclude a switching network 811 that may be composed of a network ofswitches that interconnect the outputs of the relays 778-806 todifferent load-side terminals 812.

By way of example, the switching network 811 may include a subset ofswitches for each set of relays (e.g., 778, 780, 782) connected to asubset of the load-side terminals 812 associated with a particularmotor. The subset of switches may enable each individual relay of theset of relays (e.g., 778, 780, 782) to connect to any one of the subsetof load-side terminals 812, such that a wire mistakenly placed in oneload-side terminal 812 may be internally routed via the switchingnetwork 811 to the correct relay (e.g., 778, 780, 782).

In addition, the switching network 811 may facilitate changing therouting between any individual relay disposed on the PCB 776 to anyindividual load-side terminal 812. In this way, if the control circuitry816 detects that the load-side terminals 812 are incorrectly wired toconnect one output of a relay to a motor that is not associated with therelay, the switching network 811 may automatically reroute theincorrectly wired load-side terminal 812 to the correct relay output.

By automatically adjusting the circuit connections on the PCB 776 toroute the wiring that controls a particular motor M_(N) to theappropriate motor controller MC_(N), the time associated with theinitialization process of the motor controllers MC_(N) coupled to thePCB 776 may be reduced, thereby reducing the time for assembling andmanufacturing motor control systems. That is, motor controllers MC_(N)may be coupled to the PCB 776 without regard to how each motorcontroller MC_(N) is physically positioned on the PCB 776. Instead, theswitching network 811 may connect the appropriate load-side terminals812 for a corresponding motor M_(N) to the corresponding relay of thePCB 776. Additionally, the initialization process may also minimize theprobability of incorrectly wiring such motor control systems duringassembly and manufacturing because the control circuity 816automatically determines and connects each motor controller MC_(N) withthe appropriate motor M_(N) through the PCB 776.

After the control circuitry 816 of the PCB 776 has performed theinitialization process described above, the control circuitry 816 maymonitor and control the operation of one or more relays 802, 804, 806 ofeach motor controller MC_(N) on the PCB 776. For example, the controlcircuitry 816 may detect the number of relays 802, 804, 806 anddetermine the number of motors M_(N) the PCB 776 is capable ofcontrolling. The control circuitry 816 of the PCB 776 may then determinethe number of motors M_(N) currently coupled to the PCB 776 and disableany relays 802, 804, 806 that are not currently connected to such motorsM_(N). For instance, the control circuitry 816 may detect that twelverelays are present on the PCB 776 and that the PCB 776 is capable ofcontrolling four motors. However, after performing the initializationprocess described above, the control circuitry 816 may determine thattwo motors M₁, M₃ are currently connected to the PCB 776. The controlcircuitry 816 may disable the relays 784, 786, 788, 796, 798, 800 of themotor controllers (e.g., MC₂ and MC₄) that are not currently in use tocontrol a corresponding motor. In this way, the control circuitry 816may increase the power efficiency of the motor control system bydisabling any relays that are not currently in use.

Additionally, the control circuitry 816 of the PCB 776 may automaticallyconfigure a collection of relays (e.g., the relays 802, 804, 806 of eachmotor controller MC_(N)) on the PCB 776 to operate according todifferent current ratings based on the type of motors M_(N) coupled tothe PCB 776 and/or the number of motors M_(N) coupled to the PCB 776.For example, the control circuitry 816 may configure one or more relays802, 804, 806 (e.g., a 16-amp relay) to support two lower amp-ratedmotors or one higher amp-rated motor via the initialization processdescribed above. Additionally, the control circuitry 816 may provide arecommendation to add one or more jumpers to the PCB 776 to makeappropriately rated relay connections based on the number and/or thetype of motors M_(N) currently coupled to the PCB 776. Accordingly, thePCB 776 may provide motor control systems with an increase inflexibility between various applications, thereby reducing the number ofPCBs needed to implement such applications.

In some embodiments, the control circuitry 816 of the PCB 776 maymonitor the temperature of the line-side terminals 810 or the load-sideterminals 812. Temperature sensors, such as thermocouples and the like,may measure the temperature of the line-side terminals 810 and/or theload-side terminals 812 and relay the temperature data to the controlcircuitry 816 of the PCB 776. Upon determining that the temperature of aparticular line-side terminal 810 and/or a particular load-side terminal812 has exceeded a given threshold, the control circuitry 816 mayprovide a visual indication or an audible indication. For example, theindication may represent a recommendation for retightening of the wiresconnected to the particular line-side terminal 810 and/or the particularload-side terminal 812. In some embodiments, the indication may beprovided on a visualization depicted in a display, or the like.

Technical effects of the embodiments described herein include reducingthe time of assembling and manufacturing motor control systems byallowing motor controllers to be coupled to a PCB without regard to howeach motor controller is connected to a corresponding motor through thePCB (e.g., as compared to individually labeling wires to be routedbetween motor controllers and a control system). Additionally, theprobability of incorrectly wiring such motor control systems duringassembly and manufacturing may be minimized. Further, by monitoring andcontrolling one or more relays on the PCB (e.g., disabling or activatingthe relays) during operation based on motors currently being controlledby the PCB, the power efficiency of the motor control system mayincrease by disabling any relays that are not currently in use.

It should be noted that although certain embodiments described hereinare described in the context or contacts that are part of a relaydevice, it should be understood that the embodiments described hereinmay also be implemented in suitable contactors and other switchingcomponents. Moreover, it should be noted that each of the embodimentsdescribed in various subsections herein, may be implementedindependently or in conjunction with various other embodiments detailedin different subsections to achieve more efficient (e.g., power, time)and predictable devices that may have a longer lifecycle. It should alsobe noted that while some embodiments described herein are detailed withreference to a particular relay device or contactor described in thespecification, it should be understood that these descriptions areprovided for the benefit of understanding how certain techniques areimplemented. Indeed, the systems and methods described herein are notlimited to the specific devices employed in the descriptions above.

While only certain features of the disclosure have been illustrated anddescribed herein, many modifications and changes will occur to thoseskilled in the art. It is, therefore, to be understood that the appendedclaims are intended to cover all such modifications and changes as fallwithin the true spirit of the disclosure.

1. A system, comprising: a single-pole switching device, comprising: aplurality of armatures associated with a plurality of phases of voltagesignals, wherein each armature is configured to move between arespective first position that electrically couples a respectivearmature to respective first contact and a respective second positionthat electrically couples the respective armature to a respective secondcontact; a plurality of coils, wherein each coil is configured receive arespective voltage configured to magnetize a respective coil, therebycausing the respective armature to move from the respective firstposition to the respective second position; a control system configuredto: receive an indication that a fault condition is present, wherein thefault condition is associated with a first armature of the plurality ofarmatures; identify a first phase of the plurality of phases of voltagesignals that is expected to be the next phase of the plurality of phasesto cross zero; and send a signal to the single-pole switching device inresponse to identifying the first phase, wherein the signal isconfigured to cause a first coil of the plurality of coils to energizeor deenergize.
 2. The system of claim 1, wherein the fault conditioncorresponds to an overvoltage condition, an overcurrent condition, atemperature condition, an overload condition, or any combinationthereof.
 3. The system of claim 1, wherein the control system isconfigured to receive the indication in response to a change in currentexceeding a threshold.
 4. The system of claim 1, wherein the controlsystem is configured to receive the indication from one or more sensors.5. The system of claim 1, wherein the control system is configured toidentify the first phase based on an expected waveform signal tracked bythe control system.
 6. The system of claim 1, wherein the control systemis configured to send a second signal in response to detectingidentifying the first phase, wherein the second signal is configured tocause an actuator to control a position of the first armature.
 7. Thesystem of claim 1, wherein the signal comprises at least one constantcurrent pulse provided to the first coil.
 8. A system, comprising: anarmature configured to move a first contact between a first positionthat electrically couples the armature to the first contact and a secondposition that electrically couples the armature to a second contact acoil configured receive a voltage output by a voltage source, whereinthe voltage is configured to magnetize the coil, thereby causing anarmature to move between the first position to the second position; anda controller configured to: receive an indication of a presence of anexternal event that corresponds to physically disrupting a position ofthe armature; determine an expected position of the armature prior tothe external event; and adjust power provided to the coil based on theexpected position and the indication.
 9. The system of claim 8, whereinthe external event causes the armature to move from the expectedposition.
 10. The system of claim 8, wherein the power is configured tocause the coil to overcome an external force created by the externalevent.
 11. The system of claim 10, wherein the external forcecorresponds to a vibrational or mechanical force.
 12. The system ofclaim 10, wherein the external force corresponds to a fault condition.13. The system of claim 12, wherein the controller is configured toadjust the power provided to the coil by adjusting a current provided tothe coil.
 14. The system of claim 8, wherein the controller isconfigured to provide a current to the coil prior receiving theindication, wherein the current corresponds to a minimum value to keepthe armature in the expected position.
 15. A method, comprising:receiving, via a processor, data associated with a change in current;determining, via the processor, whether the change in current exceeds athreshold; and sending, via the processor, a signal to an actuatorcoupled to a single-pole switching device in response to the change incurrent exceeding the threshold, wherein the signal is configured tocause the actuator to move a contact within the single-pole switchingdevice.
 16. The method of claim 15, wherein the actuator is configuredto separate the contact from an additional contact within thesingle-pole switching device.
 17. The method of claim 15, wherein thechange in current is associated with a current exceeding a secondthreshold within a period of time.
 18. The method of claim 15, whereinthe threshold is determined based on a relationship between the contactand a change in current value that corresponds to the contact moving.19. The method of claim 15, wherein the data comprises a detected fault.20. The method of claim 15, the data comprises an inductance associatedwith the actuator.